The Hard-Disk Explosion High-Powered Mass Storage for Your Personal Computer

Tom Manuel 1208 Apollo Way, Suite 502 Sunnyvale CA 94086

High-performance, high-quality, new small sizes-200 mm (7.87 inch) drives, especially where multiple and large-capacity hard-disk drives or 210 mm (8.27 inch) diameter-and drives would normally be neces­ are now a low-cost reality for your one new drive uses 130 mm (5.12 sary to obtain enough storage. personal-computer system. Most inch) platters. Even so, their data For example, instead of adding hard disks use Winchester media, capacities are significantly larger than more floppy drives to increase head technology, and other modern floppy-disk drives of the same ap­ the storage capacity of a system, techniques to achieve high density proximate size. one set of dual floppy-disk drives and high performance in a small The latest disk drives can be divid­ might be replaced with an 8-inch space. One side effect is low power ed into two general categories: hard-disk drive that fits in the consumption. Some of the drives suit­ same space. This improves the able for personal computers use the • low-cost, relatively low­ storage capacity and system per­ older 14-inch standard diameter plat­ performance drives that will formance dramatically. These ters. Many new drives use one of two eventually replace floppy-disk low-end disk products will com­ pete on a cost-per-drive basis. • high-capacity, top-performance drives that must compete on a cost-per-byte basis. The 8-inch or smaller versions will likely (at least at first) be more costly per byte than the 14-inch models. However, their advantages of small size, light weight, low noise, and low power re­ quirements make them very at­ tractive for desktop and personal computers as well as small business systems.

The Winchester disk-drive tech­ nology developed by IBM provided expensive, large-capacity, high-per­ formance, and low cost-per-byte disk subsystems (ie: the IBM 3350 and 3370 disk-drive systems) for large, ex­ pensive computer systems. This technology and development in other areas of disk-drive performance are now being applied to the develop­ ment of products suitable for smaller systems. The tremendous growth of Photo 1: The Memorex Model 101 hard-disk drive. (Photo courtesy of Memorex') microcomputers has created a de-

58 August 1960 © BYTE Publications Inc mand for small, compact disk drives. What Is Winchester T echnology7 • thinner magnetic coating: 44 The industry has responded and is be­ Three disk technologies have micro inches versus 185 micro­ ginning to produce them. A evolved, all pioneered by IBM. Other inches in the 2314 disk drive Winchester disk drive for your per­ manufacturers have refined the • lubricated disk surfaces sonal computer is now, or soon will designs. These technologies are usual­ • heads resting on disk surface be, a possibility. However, it may ly referred to by the model numbers when drive is stopped-they take still cost you five to ten times the of the original IBM product employ­ off and fly low when motion price of your processor to get a com­ ing the technology: "2314" starts (normal take-off and land­ plete small hard-disk subsystem with technology (in the 1960s), "3330" ing are done on an area reserved drive, controller, interface, power technology (late 1960s, early 1970s), for that purpose) supply, and packaging. and 'Winchester" technology (1973). • light loading force (10 g) and Disk storage, being a special type lighter heads. of add-on memory, can directly affect a computer system's performance, These characteristics permit many throughput, and reliability. Because performance improvements: very low of this crucial role, the principal flying heights (19 to 20 microinches), design objectives for disks are large improved reliability, and a dramatic capacity, fast access time, absolute reduction in head crashes are possible reliability, and low cost. because of the clean environment, Each of the three advances has new head and loading designs, and brought a significant increase in lubrication. Data densities are in­ storage density. One way to increase creased because of lower flying height density is to reduce the flying height and thinner platter coating. The of the heads over the disk surface. higher densities improve throughput Each reduction in height allows an in­ performance directly. More bits per crease in: tpi (tracks per inch) and bpi inch allow more data to pass under (bits per inch) (see figure 1). Ad­ the heads per unit time. More tracks vances in head design and positioning per inch mean that track-to-track ac­ mechanisms have also contributed to cess times are shorter. The lighter increases in tpi and bpi. heads and head mounts have less in­ Head flying heights have evolved ertia and can be positioned faster. as shown in table 1. Throughput performance can be im­ Photo 2: Close-up of a Winchester-type Just prior to 1973, disk-drive proved by increasing the rotational read/ write head. (Photo courtesy of Kennedy Company.) technology approached some limits. speed, up to a point-the aero­ The flying height had been reduced to dynamic characteristics of the flying 31 microinches. Without further head put some constraints on the reduction, significant improvement in rotational speed. The reliability of the data density was difficult. At lower Winchester drives surpassed that of flying heights, a single smoke parti­ any moving-head disk drive that was cle, whose diameter may be up to ten previously available. times the distance between the head Improvements and refinements and disk surface, can damage the disk have continued from many manufac­ and data. Therefore, cleaner condi­ turers. The costs of many of the most tions were required. Also, the disk expensive elements in a disk (the platters and magnetic surfaces were motor, head actuator, and control inadequate for large increases in track electronics) are relatively indepen­ and bit densities. dent of the capacity of the disk plat­ The 3340 Winchester disk drive, in­ ters. It is, therefore, cost-effective to troduced by IBM in 1973, was the increase the density of the platters first breakthrough. Storage and the number of platters. The in­ Technology Corporation announced centive has been to add capacity by a similar disk drive around the same any conceivable means, and trends time: the STC 8800 superdisk. have been toward more platters per spindle and greater bpi and tpi den­ Winchester Characteristics sities (data density has gone from Photo 3: The remarkable Shugart Winchester disk drives have the about 1000 bpi on early 2314s to over Technology Model ST506 hard-disk following characteristics: 8600 bpi on some of the recent disks, drive, offering 6 megabytes of mass and tpi density has gone from 200 tpi storage in a 3.5-pound package that fits in • sealed disk, head, and position­ on 2314s to over 600 tpi on new pro­ the ' same space as a 5-inch floppy-disk ducts). Cost effectiveness has also drive. (Shugart Technology is a new com­ ing assemblies pany located in Scotts Valley, California, • new trimaran head design-two been enhanced by reducing the access and is not affiliated with either Shugart outriggers supporting a narrower time and increasing the data flow; the Associates or Xerox. Photo courtesy of inner hull containing the economic payoff is increased Shugart Technology.) read/write head (see photo 2) throughput and efficiency of the total

60 August 1980 © BYTE Publications Inc system. In applications where disk come from RPS (rotational postion­ because twice the amount of data can storage is a key element, the pro­ ing sensing), which frees the disk con­ be read or written without moving cessor is often disk-IIO-bound. Pro­ troller and 110 (input! output) chan­ the heads. gram execution speed depends on nel for other work during seek time disk speed. Every increase in (head actuator movement) and dur­ Comparing the New Hard Disks throughput will improve the total ing part of the rotational delay time. to Floppy-Disk Drives performance. Improvements have also included The current trends toward multi­ Other improvements in throughput new automatic error detection, cor­ terminal ' systems, real-time transac­ performance in disk subsystems have rection, and recovery capabilities tion oriented systems, small business built into disk controllers. systems, and more powerful personal Voice-coil actuators, described in computers for a great variety of ap­ the next section, are common on plications have created a demand for high-performance disk drives. There more on-line data storage. Floppy­ are both linear and rotary voice-coil disk drives and tape cassettes often do positioners. Rotary voice coils not have the required performance typically take up less space, require (access times, throughput, etc), less power, and generate less heat reliability, or capacities. Thus, the than linear voice coils. Stepper need for secondary storage is being motors with band actuators are filled by new, inexpensive, high­ usually used in lower-performance, performance, highly reliable small­ lower-cost disk drives. Many of the disk drives with capacities, speeds, new small drives use brushless DC and reliability close to the very ex­ (direct current) motors with direct pensive drives. These new drives are drive on the platters. Designed as part physically much smaller and more of the spindles, these motors are com­ reliable than 14-inch cartridge or pact (about 1 inch high), maintain disk-pack drives. They are aimed in­ speed more accurately, use less itially at a gap between floppy drives power, and require simpler power and 14-inch drives (eg: Winchester, supplies than AC (alternating cur­ 5440 cartridges and 3330 type packs). rent) motors with belt drives. In They are designed for use on small many drives, each recording surface business systems, distributed­ Photo 4: BASF Systems' 6170 Series is split into inner and outer bands processing systems, word-processing 8-inch, fixed hard-disk drive, available in with a head for each band, reducing systems, and advanced personal com­ 8- and 24-megabyte versions. (Photo the average access time by one-half, puter systems. courtesy of BASF.) The new drives offer a lower cost per unit than 14-inch drives, and lower cost per byte than floppy-disk drives. They provide the advantages in capacity and performance of hard disks in a package the same size as an

Photo 6: Kennedy Series 7000 8-inch Photo 5: Priam 14-inch (at left) and 8-inch Winchester hard-disk drives. (Photo hard-disk drive. (Photo courtesy of courtesy of Priam') Kennedy Company.)

62 August 1980 © BYTE Publications Inc Circle 41 on inquiry card. 8-inch or even a S-inch floppy-disk mance and durability of hard disks Th. dsys of complics,.d, unf.,isb,., drive-many will actually fit the may soon be a necessity. dynsmic RAM Sf. gon.: panel openings for floppy-disk The new 8-inch and S-inch disk drives. Reliability will be better than drives offer several advantages over with floppy and cartridge drives, and both floppy and 14-inch hard drives: power consumption will be signifi­ cantly lower than that of the 14-inch • They have five to sixty times the drives. storage capacity of a floppy-disk Systems based on 16-bit processors drive in the same space. INTRODUCING or microcomputers often require • They access data four times faster much more and much faster secon­ than the floppy-disk drive. dary storage than floppy disks can • They weigh less, take up less provide. The more sophisticated space, and use less power than multiprogramming and file­ 14-inch drives. the ultrabyte memory board management software currently being • They are only three to five times added to small computer systems re­ more expensive than floppy-disk COmpl,t,;it ) 95 (with 16K memory quires so much continuous use of drives, with cost reductions like­ $199. mass storage that the high perfor- ly. Netronics consistently offers innovative products at un­ beatable prices. And here w~ go again -with JAWS. the ultrabyte 64K Sloo memory board. The availability of low-cost-per­ ONE CHIP DOES IT All function hard disks has long been JAWS solves the problems of dynamic RAM with a awaited by the small system state-of-the-art chip from Intel that does it BII. Intel's marketplace. The wait is all but over. single chip 64K dynamic RAM controller eliminates high-current logic parts ... delay lines ... massive This summer a score of products are heat sinks ... unreliable trick circuits. scheduled to be available, at least in REMARKABLE FEATURES OF JAWS sample or evaluation quantities. Look what JAWS offers you: Hidden refresh . . . fast Though many of the new small performance ... low power consumption . . . latched data outputs ... 200 NS 4116 RAMs ... on-board TPI - BPI disk products are advertised as fitting crystal ... 8K bank select~ble ... fully socketed ... the same 4.6 by 8.S-inch opening as solder mask on both sides of board ... designed for the standard floppy-disk drive 8080. B085. and Z80 bus signals ... works in Explorer. (Shugart Technology's S-inch Micro Sol. "mizon. as well as all other well-designed Sloo computers. Winchester fits a S-inch floppy-drive BIVE YOUR COMPUTER ABiB BYTE OF MEMORY I opening, see photo 3), a floppy-disk POWERWlTNJAM-SAVEUPTrlIIOON drive cannot literally be pulled out I 11I71IODtlCTrlRY LlMITElJ.OFFER SPECIAl. PRICESI UNDECIDED? T1/Y A mllll /6/1 J4~ IN YOUR COMPIITER ON OUR and replaced by the hard drive. To /O·OA Y MOWEY- BACK OfFER ISI'fCIFY YTJI.I/ COMP/JTl1II. Figure 1: Detail of hard-disk surface, il­ begin with, the packages contain dif­ I ------~------tOlm.EITALU.I.A. cttlDfTCMDIUYEfti OIlJIlDECOM'lIlcnCUTCAU. • : CALL TOLL FREE 800·243·7428 : lustrating the ideas of tpi and bpi. ferent electronics. Most of the drives :.-NCom-"'OOrNfo'IAIICiltoS"iiE'sOEARCii6 & De~!. : I ., OEVELOPMENTLTOj 333 Litchfield Road. New Milford. CT 06776 I Please send the items checked below: o JAWS 18K RAM kit. No. 6416. SI99.95." 2314 3330 Winchester o JAWS 18K RAM lutly ....mbl.d. t.lt.d. burn.d in. Head flying height 100 to 120 31 to 45 19 to 20 No. 6416W. 5229.95." (in microinches) o JAWS 32K RAM kit. No. 6432. (reg. price S329.95). SPECtAl PRtCE U99.95.* Table 1: Evolution of head flying heights in hard-disk drives. o JAWS 32K RAM lully ....mbl.d. tllt.d. burn.d in. No . 6432W. (reg. price $369.95) . SPECIAL PRICE *339.95.* o JAWS 48K RAM kit. No. 6448. (reg. price $459.95). SPECIAL PRICE *399.95.* o JAWS 48K lully ....mbl.d. t.lt.d. burn.d in. No. 6448W. (reg. price S509.95). SPECIAL PRICE Floppy-Disk Drives Hard-Disk Drives, *449.95.* Cartridges and Disk o JAWS 84K RAM kit. No. 6464. (reg. price $589.95) . Packs SPECIAL PRICE *499.95.* I 0 JAWS 84K RAM fully ....mbl.d. t.lt.d. burned in. Standard platter a·inch 14-inch. a·inch. No. 6464W. (reg. price 5649.95). SPECIAL PRICE diameters 5-inch and 5·inch *559.95.* o Expenlion kit. JAWS 18K RAM module. to expand Capacity 100 K bytes to 1 megabyte 2 megabytes to 300 + any of the above in 16K blocks up to 64K. No. 16EXP. megabytes 5129.95." "All prices plus S2 poslage and handling. Connecticut Average Access Time 0.1 to 1 second 25 to 70 ms residents add sales tax. Total enclosed: S:-c:=-:-:--,---:-,----:::--,--- Rotational Speed 300 rpm 2400 to 4700 rpm o Personal Check 0 Money order or Cashiers Check o VISA 0 MASTER CHARGE (Bank No. ___ J Acc!. No. ______Exp. Date __ Reliability and Useful 2+ Signature ______Life Relative to Floppy· Print Name ______Disk Drives Address ______Cily ------::c---- Slate Zip,__ _ _ Table 2: Technical comparisons between floppy-disk drives and hard-disk drives, 1_'2 ~e.!!d..m.! !1~~'.!!~~~O!! ______I cartridges. and disk packs.

64 August 1980 © BYTE Publications Inc Memorex Corporation New World Computer Shugart Associates Shugart Technology Santa Clara CA Co Inc Sunnyvale CA Scotts Valley CA Costa Mesa CA

Model 10 1 21 1 SA 1002/SA 1004 ST506

Unformatted Capacity 11 .7 2. 1 5.33/10.67 6.38 (millions of bytes)

Platter Size 200 (7.87) 8 in ch 200 (7.87) 130 (5. 12) millimeters and (inches)

Number o f Platters 2 1 or 2 2

Average Access Time 70 ms 18.825 ms 70 ms 170 ms

Maximum Data Transfer Rate 756 543 625 (K bytes per second)

Ave rage Latency 10.1 ms 8.825 ms 9.6 ms 8.3 ms

Rotational Speed 2964 rp m 3600 rpm 3125 rpm 3600 rpm

Motor Type DC AC bru sh less DC

Spindle Drive direct drive belt drive direct drive

Actuator Type high speed band simplified band band band

Positioning Mechanism open loop stepper motor stepper motor stepper motor open loop stepper motor

Density bpi 6100 8000 62 70 7690

Density tpi 195 100 172 254

Physical Size 4.38 by 8.55 by 14 2 by 9.5 by 9.5 4.62 by 8.55 by14.2 5 3.2 5 by 5.7 5 by 8 (inches)

Weight (pounds) 10 8 17 3. 5

Sing le Quantity Price $4,500 $ 1,600/$1,980 $1 ,500

OEM Discount Price $1,200' $1,250 $ 1,14 0/$ 1,400 $925

Cost Per Thousand Bytes $.103 $.595 $.2 14/$ .13 1 $. 145 (OEM Discount)

Comments ' Includes a data 20 heads, 8 tracks per First micro Wincheste r separator head. Low·end only in Drive. Fi ts 5·inch fl oppy capac ity, not in space performance.

Table 3: Specifications and characteristics of low-end, 5-inch and 8-inch hard-disk drives. have the basic drive electronics, machined from pole to pole. A coil platters or it could erase them. Effi­ signal amplifiers, read/ write elec­ rides on bearings within the magnet cient design can keep the magnetic tronics, and motor and servo control and moves back and forth. The field intensity at a safe level near the circuitry integrated into the package. read/ write positioning mechanism recording surfaces. Table 2 gives a Some have room to add optional, with electromagnetic heads is partial technical comparison between separately priced controllers to do attached to the coil. A voice-coil ac­ floppy-disk drives and hard disks. error-checking a.nd correction, data tuator is positioned by serv.o-control formatting, and interfacing to the with servo tracks written on one plat­ Future Technological Progress computers. ter's surface at the factory. Some of the more recent develop­ Stepper-motor actuators are a Voice-coil actuators allow in­ ments in heads (such as thin film technique borrowed from floppy creases in data-storage capacity heads) and disks (thin-film-plated drives for use in hard-disk drives. because their accuracy in small disks) mean that data densities will This idea allowed lower prices for . movements allows high tpi densities. probably advance from the presently Winchester-technology units such as Since the distance between tracks is attainable 8 to 10 megabytes per the 14-inch Shugart SA4000 and smaller, access time is reduced. Also, 8-inch surface to 50 or more mega­ Century Data Systems Marksman, voice-coil actuators do not impose by tes per surface as track densities but at a cost of greater access time the additional penalty of settling of 1000 tpi and bit densities of 10,000 and reduced storage capacities when time. bpi are achieved. A small, relatively compared with voice-coil actuator­ One disadvantage of a voice-coil inexpensive disk drive could then based units. actuator is the magnetic field pro­ store 100 megabytes or more of data A voice-coil actuator is a cylin­ duced by the coil: the coil's magnetic with an additional 100 megabytes drical, permanent magnet with a hole field must not get too close to the disk added for nominal cost. Thin-film

66 August 1980 © BYTE Publicati ons Inc technology may be the next break­ they are still quite expensive. At least average access times ranging from through in mass-storage techniques. one interface and controller for 25 ms to 50 ms, with models that fall Secondary storage and storage American and European standard into both size categories. The less ex­ backup are currently being supplied VCRs (videocassette recorders) is pensive units are aimed at replacing by a wide variety of devices, available to provide removable back­ floppy-disk drives directly. Examples including up for high-capacity disks on small of this type of product are the systems (the Corvus Mirror, manu­ cassette tapes Memorex 101, the Shugart Associates factured by Corvus Systems Inc, San SA-lOOO series, and the Shugart 8-inch floppy-disk drives Jose, California). It stores up to 100 Technology ST 506. The high end is 5-inch floppy-disk drives megabytes on one videocassette and reel-to-reel magnetic tapes led by IBM with the Piccolo drive, has a transfer rate of 15 K bytes/se­ which is integrated into the System cartridge magnetic tapes cond. Video disks have the potential 34, and is an add-on peripheral for cartridge-disk drives to offer extremely high data-storage disk-pack drives the Series 1. It features a rotary voice capacity and fast access rates (up to coil, 17 ms average access time, and fixed storage Winchester drives 1250 megabytes per 12-inch disk, up to 64 .5 megabytes of storage combinations: fixed Winchester- equal to approximately four times the capacity . Other contenders in this disk/ cartridge-disk drive or contents of the Encyclopaedia Britan­ ca tegory offer high performance in a fixed Winchester /magnetic­ nica). wide range of sizes (eg: the BASF tape cartridge Systems 6170 Series, IMI (Interna­ streaming-tape drives Small vs Large Hard-Disk Drives tional Memories, Inc) 7700 Series, bubble memories Hard-disk drives for small systems Kennedy Company 7000 Series, nonvolatile semiconductor fall roughly into two size categories: Microcomputer Systems MSC-8000, programmable memory up to 12 megabytes and over 12 Micropolis Corporation Micro Disk videocassette recorders megabytes; and two performance 1200 Series, Pertec Computer Cor­ video disks categories: slow, with stepping-motor poration 0 -8000, and Priam Oiskos The last three or four types are positioning, and fast, with voice-coil 2050/3450). more for the future than now. Bubble positioning. Those with stepping­ The disk capacity and the perfor­ memories and nonvolatile integrated motor positioning have average ac­ mance you need depend on your par­ circuits will have the great advantage cess times of 70 ms and capacities of ticular application, which in turn has of no moving parts and the potential under 12 megabytes. The drives with a significant impact on the cost of a convenience of plug-in modules; but fast voice-coil positioning have system. Small-system applications, as

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Same day vertical line spacing • Intel 8085 Microprocessor - over shipment for VISA, MASTER CHARGE, and AMERICAN EX· Orange 40 software commands • Self test • 15 Baud rates to PRESS. Personal checks require 2 9600 Baud • Optional foreign character sets weeks to c lear. Add 3% for ship· ping and handling. California resi· micro Interfaces to TRS·80, Apple, Atari, PET, Northstar, and most dents add 6%. Manufacturer's P.O. Box 2076 warranty included. Prices subject to Yorba Linda, CA 92686 other computers. revision. Ci rcle 44 on i mentioned before, can be placed in They typically require from 30 to $1000 to $5000 (some may soon drop two major classes: single-user, single 100 megabytes of magnetic below $1000), both classes of the new task and multi-user, multi-task. storage, usually on one spindle. hard-disk drives should be attractive Some require less storage and to personal-computer systems • Single-user, single-task systems some will require multiple builders who want additional are usually stand-alone work­ spindles. The cost per byte of capacity and performance, but not stations, intelligent terminals, or storage is a more important con­ the traditional 14-inch disk size and personal computers. Their chief sideration than the cost per drive price per unit. Some complete use of magnetic storage, in unit, because the basic device packages of drives, controllers, inter­ general, is for program storage cost is spread over many users. faces, and power supplies are and data storage. The amount of available for about $5000. Even storage required is often less than Multi-user, multi-task systems re­ though they cost five to ten times as 10 megabytes. Because the speed quire an average access time of 50 ms much as the processor, these units are need only match one human or less because multiple users must still cheaper per drive than 14-inch operator's response time, there is contend for the common storage de­ drives. They are also applicable no benefit to be derived from vice. The main purpose of these ap­ where more capacity and perfor­ disks with extremely fast access plications is usually not to share the mance than a floppy disk can supply times. An average access time of processing power, but rather to share are needed, but the space or the cost 70 ms is usually sufficient in such the data. These systems are often of a 14-inch disk drive is prohibitive. applications. This class of ap­ "disk-bound" rather than "computer­ Tables 3, 4, and 5 list some of the cur­ plication is cost-per-unit­ bound." Disk performance becomes a rent disk-drive products for small oriented, since the storage device critical factor in system performance. systems. The reliability and main­ is dedicated to one user. It is Even when the disk capacity required tainability of these products are price-oriented, and performance might be relatively small (8 to 10 essentially high and are consistent is not a vital factor. The low-end, megabytes), the fast performance of across the board. (See table 6.) small hard-disk drives fill this the high end mini-disks will be re­ need splendidly. quired. Controllers and Interfaces • Multi-user, multi-task systems re­ With their faster access times, One of the problems with the new quire that more than one, higher capacities, greater reliability 8-inch hard-disk drives is the variety sometimes many, users have ac­ and OEM (original equipment manu­ of interface systems to choose from. cess to a common data base. facturer) quantity prices ranging from Such variety is inevitable at this stage ------, because of the many personal com- puters already on the market, and the diversity of interface requirements. In the absence of a comprehensive inter­ face standard, many of the drive sup­ pliers have designed their own. A similar situation has developed in the audio industry. Consider the many types of noncompatible audio record­ ing standards including: the LP (long­ playing) record, 45 rpm records, open reel tapes, cassettes, and eight-track cartridges. This kind of variety at the outset of new products is not neces­ Relocatable Object Modules. sarily bad-there is much freedom for innovation. Reduced Compile Time. AND MORE! In August of 1979 an ANSI (Amer­ Meet our new, improved Pascal/Z!M The true Z-80 ican National Standards Institute) compiler that's 5-10 times faster than P-code, and Subcommittee (number X3T9.3) produces ROMabie re-entrant code for true multi-tasking began to standardize an interface for capabi I ity. 8-inch hard disks. If a standard inter­ Our new compiler adds features like variant rec­ face is widely accepted by the in­ ords, strings and random access. Also included are an dustry, users may soon be able to in­ improved macro-assembler that generates Microsoft­ terface drives from several vendors. compatible relocatable object modules; a linker/ loader and source on the full Ii.brary. All six programs on a Types of Interfaces CPlM®-compatible disk , $395. (Other formats and OEM There are two main categories of licenses available.) For more information, call or write. disk-drive interfaces, device level and host level. The main characteristics DDDrtceD~~J)V~~®DDD~ ™ for the device level are: Ithaca Inte rsyste ms. Inc. . 1650 Hanshaw Road/ PO. Box 91. • serial data transfer Ith ,lC J. NY 148,)0· 607-25 7-01 90/ TWX: 510 255 4 346 • formatting/de-formatting exter­ co lY BO , Ilhac'] Ill t e r ~ys t t:' lll ~ In c:. CPIM regislE:' rt'd tr.lci em,l(k o f D igit al Rese arch nal to drive Text continued on page 138

70 August 1980 © BYTE Publicati ons Inc Circ le 46 on inquiry card. Circle 47 on inquiry card. ~ BASF Systems Corvus Systems, Inc. IBM Corporation International Bedford MA San Jose CA General Systems Div Memories Inc (IMI) Cupertino CA

Model 6171/6172 11T 496329N64A 7710/7720

Unformatted Capacity 8/24 11 29/64 11120 (millions of bytes)

Platter Size 210mm (8.27 inch) 200mm (7.87 inch) 210mm (8.27 inch) 200mm (7.87 inch)

Number of Platters 1 or 2 2 3 or 6 2

Average Access Time 42 ms 50 ms 27 ms 50 ms

Maximum Data Transfer Rate 800 648 1030 648 (K bytes per second)

Average Latency 8.3 ms 8.3 ms 9.7 ms 8.3 ms

Rotational Speed 3600 rpm 3600 rpm approx. 3100 rpm 3600 rpm

Motor Type brush less DC brush less DC brush less DC

Spindle Drive direct drive direct drive direct drive

Actuator Type linear voice coil linear voice coil rotary voice coil linear voice coil

Positioning Mechanism servo servo servo servo

Density bpi 6542 5868 8530 5868/6000

Density tpi 500 300 450 300 Physical Size 4.59 by 8.99 by 18 5.5 by 8.57 by 19.25 5.5 by 8.57 by 19.25 (inches) Weight (pounds) 20 22 22

Single Quantity Price -1$3,100' $5,350' approx. $9,300/$10,700 $2,9901$3 ,590

OEM Discount Price Competitive OEM $1,900/$2,290 (100) discounts available

Cost Per Thousand Bytes -1- $.173/$ .112 (OEM Discount)

Comments Available with integrated Up to 4 drives per Integrated into System/34. Optional integrated SMD interface @$3,500 subsystem. Add-on drives Add-on peripheral for controller available and integrated controller @$2,990. Uses IMI 7710 Series 1. @$500 (quantity 1); $325 with host bus interface for drive. (quantity 100). Powe r $3,900; all prices quoted supply @$250 are for 24 megabyte Model 6172. 1. Includes disk bus 2. Complete subsystem interface

Text continued from page 70: • SMD serial NRZ (nonreturn-to-zero) for­ • hardware-oriented control and • Floppy-disk-Iike mat separated from the clock signal. status In the ANSI-like interface, most of The ANSI interface, as far as it is the current device-level interfaces are The main characteristics for the host currently defined, will use a single more or less similar to the ANSI inter­ level are: SO-conductor flat cable. Up to four face_ Common to all are an 8-bit drives can be connected in a daisy­ parallel control bus and serial NRZ • parallel data transfer chain configuration_ Differential data transfer. drivers and receivers will be used • formatting/de-formatting SMD (storage module drive) inter­ included in drive electronics only for block and data signals for face is a de facto industry standard • function-oriented control and read and write functions. All other status by functional command lines will use standard TTL for 14-inch drives and is being like read/write sector and (transistor-transistor logic) signals. adapted for 14-inch drives by ANSI. format Control commands and status infor­ It has also been implemented for mation will be transferred over an 8-inch drives. The SMD interface uses Device-level interfaces can be 8-bit-wide bidirectional bus. The bus differential drivers and receivers for divided into four groups: control lines use an asynchronous all signals_ (They give excellent per- handshake. mechanism, allowing sim­ formance as regards high speed, long • ANSI ple adaptation of the bus speed to any cable lengths, and high noise immuni­ • ANSI-like microprocessor. Data is transferred in ty .) The drives are connected through

138 August 1980 © BYTE Publications In c Kennedy Co Microcomputer Systems Micropolis Corp Pertec Computer Corp Priam Altadena CA Corp Chatsworth CA Chatsworth CA San Jose CA Sunnyvale CA

7000 MSC-8000 1201-1/1202-1/1203-1 D8000 2050/3450

4/12/20 40 9/27/45 20 20/34

210mm (8.27 inch) 8 inch 200mm (7.87 inch) 210mm (8.27 inch) 8 inch

1,2, or 3 3 1,2, or 3 2 2or3

50 ms 25 ms 42 ms 50 ms 50 ms

1200 922 870 1030

8.3 ms 8.3 ms 6.4 ms

3600 rpm 3600 rpm 4700 rpm AC brush less DC brush less DC

belt drive direct drive direct drive rotary rotary voice coil linear voice coil

servo servo servo servo

5280 8626 6000 6370

300 478 476 480

5.25 by 8.5 by 16.5 4.62 by 8.55 by 14.25 4.62 by 8.55 by 14.25 4.62 by 8.55 by 14.25

20 22 20

$2,1001$2,3001$2,650 $1,962/$2,591/$3,007 $3,000 $3,0001$3,750

$1,6801$1,8401$2,120(100) $1,800 $2,2001$2,750(100)

$.42/$.153/$.106 $.09 $.11/$.08

Included in package is Available with integrated an 80 megabyte, '12 inch controller as Models: magnetic-tape drive on 1221-1 $2,834; 1222-1 the same motor spindle $3,463; 1223-1 $3,879, for removable back-up Single quantities storage

Table 4: Specifications and characteristics of high-end, 8-inch hard-disk drives.

one daisy-chain cable for control and Having a floppy-disk-like interface ences. First, with floppy-disk-like in­ one radial cable for read/ write and for 8-inch hard disks allows the com­ terfaces there is no control bus be­ additional control. Control informa­ bination of floppy-disk drives and cause commands and status signals tion is transferred on a lO-bit-wide hard-disk drives in one system. are transferred on discrete lines. unidirectional synchronous bus. Data Because of the differences in transfer Second, positioning control is is transferred in serial NRZ format. rates and other parameters, floppy­ achieved with step and direction The SMD interface allows very and hard-disk drives are not fully signals as opposed to the transfer of a high transfer rates and long cable interface-compatible. Hard-disk users parallel-cylinder address with other lengths. Because SMD uses differen­ must add a radial cable for differen­ interfaces. Third, data is transferred tial drivers and receivers for all tial read/ write signals in addition to in the raw format as recorded on the signals, it is somewhat more costly the normally used daisy-chain cable. disk. This implies that synchroniza­ than other interfaces using TTL cir­ By adding 15 % to 20 % more cir­ tion, separation (or generation) of cuits_ Because of the 10-bit syn­ cuitry, a hard-disk controller can be clock and data, and generation and chronous bus structure, SMD is not designed to also control floppy-disk detection of sector and address marks easy to interface to current 8-bit pro­ drives. However, a floppy-disk con­ must all be performed externally to cessors. The main advantage of SMD troller cannot handle a Winchester­ the drive. The floppy-disk-like con­ for 8-inch drives is that it is a stan­ type hard-disk drive. cept minimizes drive electronics, but dard, and controllers are readily In comparing floppy-disk-like in­ puts the burden of developing and available for easy integration into ex­ terfaces with other device-level inter­ producing the balance of the required isting or currently supplied systems. faces, there are three major differ- electronics on the user.

August 1980 © BYTE Publications In c 139 Century Data Systems Century Data Systems Fujitsu America Inc Anaheim CA Anaheim CA Santa Clara CA

Model Ma rksman M-10/M-20/M-30 Hunter H-32/H-64/H-96 M2282/M2283/M2284

Unformatted Capacity 10/20/30 34/67/100 66/133/166 (millions of bytes)

Platter Size (inches) 14 14 14

Number of Platters 1,2, or 4 2,3, or 4

Average Access Time 60 ms' 30 ms 27 ms

Maximum Data Transfer Rate 960 1209 1012 (K bytes per second)

Average Latency 12.5 ms 8.3 ms 10.12 ms

Rotational Speed 2400 rpm 3600 rpm 3000 rpm

Motor Type

Spindle Drive

Acutator Type band rotary

Positioning Mechanism stepper motor servo servo

Density bpi 6475

Density tpi 668

Physical Size (inches) 8 by 16.5 by 21.5 10.5 by 17.5 by 30 10.3 by 18.9 by 26.6

Weight (pounds) 45 175 100

Single Quantity Price $4,3501$5,2001$5,500

OEM Discount Price $3,4501$4,3001$4,600 (quantity 100)

Cost Per Thousand Bytes $.052/$.033/$.028 (OEM Discount)

Comments Winchester Technology 16.7 megabytes of removable Optional 655 K byte fixed head storage on each model storage for $700 (5440 Type) , in cludes settling time

Host-Level Interface functions, rather than tying up the of tracks per surface will likely be dif­ A typical implementation for host­ processor. ferent. This information must be level interface is the BASF 6170 series These subsystems can communi­ communicated to the operating drive with integral formatter/con­ cate with the main system through a system. (With luck, this is a small troller. The BASF host bus interface high-level command language (eg: parameter change in the lIO driver of uses a single daisy-chain cable that one that is file-oriented as opposed to a well-designed, modular operating can connect one or more units to the hardware-oriented). Functions such system). But, however easy or dif­ host adapter. Transfer of data, com­ as automatic backup, automatic error ficult it is to change, it must be done mand, and status information is done recovery, power-on bootstrap load­ to take full advantage of the new across one common 8-bit-wide bi­ ing, etc, can be completely controlled higher-capacity drive. directional asynchronous bus. The locally in the subsystem, thus taking eight bus lines, as well as additional the burden off the main processor and The Question of Backup for Fixed lines for bus control and interrupt improving the system's performance. Disks generation, all use standard TTL Further improvement can be gained The usefulness of removable media drivers and receivers. Using a host­ by adding hardware and software for on fixed-disk-based systems arises level interface is the easiest and fastest such things as double-buffering for from three needs: way to interface an 8-inch Winchester data transfer, overlapped operation drive to a given host system. in a multiple drive configuration, and • system backup for crash/ fault RPS (rotational-positioning sensing) recovery How Intelligent Should a Con­ for access optimization. • program and data-base troller Be? There is a limit to the transparency dissemination With the decreasing cost of of the disk system to the operating • archival storage of information microprocessors and memories, the system. If a disk with higher packing trend is toward the use of intelligent density is substituted, the number of The excellent reliability record of subsystems to handle all lIO-related sectors on each track or the number Winchester-technology disks is caus-

142 August 1980 © BYTE Publications Inc Fujitsu America Inc Kennedy Co Priam Shugart Associates Santa Clara CA Altadena CA San Jose CA Sunnyvale CA

M2201/M2211 5300 335016650/15450 SA4000 50/83 14/42/70 33/66/154 14.5129 14 14 14 14

2or3 1,2, or 3

30 ms 70 ms 50 ms 87 ms

819 1030

12.5 ms 10 ms 9.7 ms

2400 rpm 3000 rpm approx. 3100 rpm

AC brush less DC

direct drive

linear motor rotary linear voice coil band

servo servo servo stepper motor

61 35 6000 6370 5534

370 300 480/9601- 172

10.3 by 19 by 30.2 7 by 19 by 22 6.8 by 16.6 by 20

150 75 33 $5,4001$7,200 $3,2001$3,7001$4 ,200 $3,9001$4 ,990 (quantity 100) $2,5601$2,9601$3,360 $ 1, 800/- /- (quantity 100)

$.0781$ .060 $. 1831$ .07/$048 $.0551- 1-

Front-loading cartridge Win chester Technology Winchester Technology Winchester Technology removable storage

Table 5: Specifications and characteristics of 14-inch, hard-disk drives.

ing some system builders and users to reliability of the fixed-storage subsys­ ducts still have a place in some small take a fresh look at backup re­ tem. System crashes or failures can be systems. After all, the backup pro­ quirements for data storage. They are caused by software bugs and human blem is solved, whereas no generally concluding that, for some applica­ error as well as by hardware faults. accepted backup method has yet tions, it is no longer necessary to in­ Until the new wave of small emerged for the "mini Winnies" to clude removable media for backup Winchester disks came on the scene make most customers feel comfort­ protection in systems design. beginning about a year and a half able. It is a problem yet to be solved. Error-correcting capabilities of sys­ ago, the small-systems hard-disk Several approaches are being tried tem software and intelligent control­ market was being served primarily by for backup. There are floppy disks, lers help to eliminate the need for products based on IBM 5440-type tape cassettes, tape cartridges, reel­ backup in some cases. However, removable-cartridge disk technology. to-reel tape drives, and, in at least there will probably always be appli­ Most of these products have the uni­ one case, videocassettes. cations-perhaps the majority-in que characteristic of having 50% of The ideal characteristics of a which backup cannot be eliminated. their spindle capacity removable-in backup device are: Many systems require removable me­ other words, they have built-in dia for program and data-base dis­ backup. But the major drawbacks to • The cost of the modular semination and/ or archival storage in their use in small systems are relative­ removable medium should be addition to any backup considera­ ly low performance (70 ms average low (less than $20). tions. Therefore, it seems that there access time); relatively high cost per • The cost of the transport device will be a continuing need for remov­ byte; large physical size; and high should be low. able-media storage peripherals on maintenance costs that get higher as • The data-transfer rate should be some fixed-disk-based systems. field engineering labor costs grow. similar to the transfer rate of the According to many small-system Even with the introduction of cost-ef­ disk. designers and users, system backup is fective, small, reliable Winchester­ • A single removable module needed regardless of the hardware type products, these 5440-based pro- should hold more, or at least as

August 1980 © BYTE Publications Inc 143 Error Rates

Recoverable Unrecoverable Seek Errors

1 in 10'0 bits 1 in 10'2 bits to 1 in 1 in 10· seeks to 1 in 1013 bits 10' seeks

Maintainability

Preventive Maintenance (MTBF) (Mean Time (MTBF) (Mean Time (MTTR) (Mean Component Life Between Failures) Between Failures) Time to (sealed modules) (product) Repair) None 25,000 hours 8000 to 10,000' Y2 to 1 hr 5 years POH (power-on hours)

• Exception: Kennedy 7000 Series, 1500 hours

Table 6: Reliability data for hard-disk drives.

Call on John D. Owens for all Your Computer Needs much, data as the fixed disk, preferably an integer multiple of COMPUTERS, PRINTERS, CRTs, MODEMS, MAINFRAMES, the disk capacity (ie: a 100-mega­ MEMORY, CONTROLLERS, FLOPPY AND HARD DISK byte videocassette to back up a DRIVES, 110, DISKETTES AND SOFTWARE. 20-megabyte disk) .

IMS 5000 and 8000 Systems With the relatively unsophisticated The new rising starsl Beautifully designed and constructed with the Industrial Micro operating-system software present in System reputation for fine quality. These systems feature a Z80 CPU, 5-100 bus; double many small systems today (though density drives (either single or double sided) CP /M®. 5000 series uses mini floppies, this is rapidly changing), the backup 8000 uses maxi floppies . strategy is usually to write the entire Model 5-00125 with two double density drives, 32K Static RAM $2,765 Model 8-00125 as above but with 8" drives ...... $4,185 cont~nts of the disk to a removable Other configurations available. backup medium on a daily basis. This procedure results in a significant loss TELETYPE Model 4320 AAK .. $1,185 IBM 3101 CRT Model 10 ...... $1,195 Model 4330 punch/ reader. 10 or 30 CPS. Model 20 ...... $1,395 in system availability (while dumping 8 level, 1" tape ...... $2,595 Selectric-like, detached keyboard. 9x16 or restoring) unless the backup device Limited supply of Model 45 available. dot matrix. Maintenance contract from has a fast transfer rate and a large IBM only $70 per year. capacity. DRIVES Per Sci 277 ...... $1,210 TELEVIDEO SMART CRTs Perhaps the most appropriate Siemens. . . .. $395 Shugart. . .. . $525 912 Band C ...... $780 backup for a small Winchester is a MPI B51 . . .. $265 B52...... $365 920 Band C ...... $850 device that can be included in the Innotronics and QUME also available IMS MEMORY 16 K static $285 same package, sharing the same 32 K static $585 spindle drive mechanism and/ or HAZELTINE 1500 ...... $885 64 K Dynamic with parity $950 1510 ...... $980 1520 ...... $1,210 some of the same electronics. For the TEl MAINFRAMES, S-100 low end this may be a floppy disk; for DEC LA 35/ 36 Upgrade ...... $750 12 slot ...... $500 22 slot ...... _ . . . . . $670 the high end it can be a cartridge tape Increases baud rate to 1200. Microproces­ drive or a streaming reel-to-reel tape sor controlled. Many features include TARBELL drive. But, except for the very low TOF, tabs and margin control. Double density controller ...... $420 end where system cost is a prime con­ COMPLETE SYSTEMS AND WORD PROCESSORS sideration, a small-capacity, slow CONFIGURED FOR YOUR PARTICULAR APPLICATION floppy disk is not an ideal backup for a large, fast, fixed disk. Streaming We have no reader inquiry number. COOs accepted at no extra charge. tape drives may be good backup Call on us for product sheets. Shipping $14 for light printers and CRTs . Dealer inquiry invited. Credit cards add 4% . devices for high-performance, high­ Prices subject to change without notice. NY residents add tax. capacity hard disks, but they are too expensive for most personal com­ . Overseas Callers: TWX 710 588 2844 WE EXPORT • Phone 212 448-6298 or Cable: OWENSASSOC puter systems. Nevertheless, some streaming tape drives are becoming We Are for• • P • • • .. available. Kennedy Company of Monrovia, California, is delivering (60 to 90 days) its Model 6809 Data JOHN D. OWENS Streamer. It is a microprocessor­ 212 448-6283 Associates, Inc. 212 448-6298 controlled reel-to-reel (10.S-inch 12 Schubert Street reels) tape transport with formatter Staten Island, New York 10305 for reading, writing, and controlling the 9-track, 100 ips (inches per

144 August 1980 © BYTE Publica tio ns Inc second), 1600 character per inch, prehensive diagnostics and interfaces offers low cost per megabyte, low ANSI- and IBM-compatible half­ for TRS-80, Apple II, S-100-bus, and weight (10 pounds), low power re­ inch tape drive. It has an unformatted LSI-11 computers. As mentioned quirements (56 W), and high reliabili­ capacity of 46 megabytes per reel. It above, Corvus also markets a ty. With 11.7 megabytes and 70 ms can transfer 12 megabytes in 75 100-megabyte removable backup in access time, it is a good example of a seconds and 40 megabytes in 250 the form of an interface to a standard product in the low-end segment of the seconds. It costs about $2500 in OEM videocassette recorder using the small hard-disk-drive market. quantities. Data Electronics Inc microprocessor and interface bus of Memorex has been manufacturing (DEI), of Pasadena, California, is the Corvus disk subsystem. IMI was disk drives since 1967 and has been a marketing a 34-megabyte streaming the first manufacturer to deliver a major supplier of magnetic media mi.crotape cartridge drive for $1219 high-performance 8-inch Winchester since the company was formed in (OEM quantities). Cypher Data Pro­ drive. 1961. The MSC-8000 from Micro­ ducts Inc of San Diego, California, Memorex Corporation of Santa computer Systems Corporation of produces a 37-megabyte streaming Clara, California, is introducing its Sunnyvale, California, is an 8-inch reel-to-reel tape drive for under $2000 first in a planned family of 8-inch disk drive with built-in removable (OEM quantities). IBM's answer to hard-disk products, the Model 101. It backup in the form of an 80-mega- the backup problem for its 8-inch disk r------­ drive is the model 8809 streaming tape drive. Call on John D. Owens for all Your Computer Needs

The Products and the Companies GROUP PLANS AVAILABLE TO COMPUTER CLUBS The specifications in tables 3, 4, and 5 speak for themselves. There are COMPLETE PET BUSINESS PACKAGE INDUSTRIAL 31 fully integrated programs including Inventory, MICRO a few special features of some of these SYSTEMS products worth mentioning. BASF Sales summary, Accounts Receivable/payable, tax TELETYPE Systems of Bedford, Massachusetts statements, general ledger, etc. etc. Prompts user. HAZELTINE Validates each entry. Menu driven. Produced in IBM (whose parent corporation, the BASF TELEVIDEO London by G .W. Computers, Ltd. TEl Group based in Germany, invented Users manual only (including postage) ...... $7 TARBELL magnetic recording tape in 1934), Complete package ...... $750 SIEMENS established a Memory Division in PER SCI Complete listing only ...... $300 NEC early 1979 to manufacture computer­ ITHACA disk drives. Their first product is the AT ARI SUMMER SALE INTER SYSTEMS MARINCHIP 6170 Series 210 mm Fixed-Disk LIST PRICE SALE PRICE Computer, Model 800 ...... $1,080 $845 DATA SOUTH Drives available in 8- and 24-mega­ QUME Disk Drive, Model 810 ...... $ 699 $545 CENTRONICS byte versions. The 24-megabyte ver­ Printer, Model 820 ...... $ 599 $457 TEXAS sion with the integrated, micro­ $ 75 INSTRUMENTS Cassette, Model 410 ...... $ 89 ATARI programmed BASF host-bus interface Paddle Controller Pair ...... $ 19 $ 17 DEC and controller at $3900 (single quanti­ CALIFORNIA MARIN CHIP SYSTEMS M9900 COMPUTER ty price, substantial discounts SYSTEMS available for OEM quantitites) is a Elegant 16 bit CPU, S-100 compatible multi-user, KONAN cost-effective, high-performance multi-processor operating system. Extended precision EDGE commercial BASIC, FORTH, META, PASCAL, TECHNOLOGY source of reliable data storage for INNOTRONICS small systems. BASF offers a variety Word Processor and Text Editor. Fast and powerful! XEROX Complete kit and software package ...... $550 DIABLO of interfaces. BASF is also a supplier INTEGRAL of disk and tape media. Assembled...... $750 DA T A SYSTEMS We configure complete systems with floppy or hard CROMEMCO Century Data Systems, a Xerox SOROC Company, of Anaheim, California, disk. MICROPRO TELETEK offers a wide range of disk products WORDSMITH Video Subsystem ...... $1,550 NOVATION for small systems including the FUJITSU S-100 Compatible, 40 lines, 80 columns. Powerful CDC 14-inch Marksman model (Win­ word processor and word processor keyboard. NORTH STAR chester technology) with capacities COMMODORE MICROANGELO ...... $1,795 SCION from 10 to ' 30 megabytes, and the MPI Hunter model with a removable High resolution graphics system. Wordsmith and POWER ONE 16.7-megabyte 5440-type cartridge, Microangel o feature 15', 22MHZ, green phospher MEASUREMENT screen, 72 key keyboard; includes complete cabling SYSTEMS AND CONTROL plus fixed-disk capacity ranging from and software. From SCION. 16.7 to 83 .9 megabytes. Century Data Systems is a long-time manufac­ SEE OUR AD AND ORDERING DETAILS ON FACING PAGEl turer of computer peripherals. Corvus Systems Inc, San Jose, California, is offering a complete JOHN D.OWENS hard-disk subsystem based on the IMI 212 448-6283 Associates, Inc. 212 448-6298 7710 10-megabyte 8-inch disk. It in­ 12 Schubert Street, cludes the Z80-based Corvus in­ Staten Island, New York 10305 telligent disk controller with com-

August 1980 © BYTE Publications Inc 145 byte half-inch tape drive on the Haines, "It's a little screamer." The reasonable price . The Shugart same motor spindle. Micropolis Cor­ Mikro-Disc 211 is a versatile storage Associates SA1000-series drives are poration, of Chatsworth, California, system suitable for a variety of uses: another example of the low-end seg­ is offering the largest capacity (now it can efficiently augment or replace ment along with the Memorex 101 available) 8-inch Winchester disk, the floppy-disk drives, supplement other with 5- and 11-megabyte models. Model 1203-1, with 45 megabytes on larger and slower mass-storage Shugart Technology of Scotts five surfaces. The density is high devices by acting as a high-speed Valley, California (a new company (8626 bpi, 478 tpi), the access time cache memory, improve system not connected with Shugart fast (42 ms), and the price reasonable. response time by providing fast-ac­ Associates or Xerox) has just an­ It is another good example of a high­ cess key-directory storage, and be the nounced its Model ST506 5-inch capacity, high-performance 8-inch primary file device in small systems. 6-megabyte Winchester disk drive. It disk in the high-end segment. New It has an assembly with twenty pro­ is the size of a 5-inch floppy drive and World Computer Company Inc, of prietary low-cost heads that write weighs only 3.5 pounds - 6 mega­ Costa Mesa, California, is making an and read data onto 0.008-inch-wide bytes of reliable Winchester disk unconventional, miniature hard disk, tracks. The head assembly is moved storage in the palm of your hand for the Mikro-Disc 211. It is a cross be­ only seven O.OlO-inch steps (eight $925 (OEM quantity 500)! In the tween a high-performance, one-he ad­ positions) across the disk. Each step is popular parlance, this is a hot little per-track disk and a cost-effective accomplished in 5 ms, precisely and product for the small computer moving head mini-Winchester drive. accurately, by a low-cost open-loop system. Evaluation units are sched­ It is small, light (8 pounds), and very stepper motor. uled to be available this month and fast (18.825 ms access time). It has The Model 3450 from Priam, San production quantities by next month. relatively low capacity (2 .1 mega­ Jose, California, is another example The latest in disk drives for small bytes) but makes up for it in perfor­ in the high-end segment, along with systems are these 8-inch and 5-inch mance, price (less than $1000 in large BASF and Micropolis. It has 34 mega­ wonders. The hard disks are upon us, OEM quantities), size (9 1J2 inch by bytes on five surfaces, fast transfer and they're taking personal com­ 91J2 inch), weight, and power re­ rate (1.02 megabytes per second), and puting forward by a giant step .• quirements (less than 50 W). In the high density (6370 bpi, 480 tpi). It is a words of company president, Phil state-of-the-art product at a

Directory of Hard-Disk Manufacturers

BASF Systems Kennedy Company Pertec Computer Corporation OEM Peripheral Sales 1600 South Shamrock Ave Peripherals Div Crosby Dr Monrovia CA 91016 9610 De Soto Ave Bedford MA 01730 (213) 357-8831 Chatsworth CA 91311 (617) 271-4000 (213) 999-2020 Memorex Corporation Century Data Systems Inc Recording Components Div Priam A Xerox Company San Tomas and Central Expys 3096 Orchard Dr 1270 North Kraemer Blvd Santa Clara CA 95052 San Jose CA 95134 Anaheim CA 92806 (408) 987-1000 (408) 946-4600 (714) 632-7500 Microcomputer Systems Corporation Shugart Associates Corvus Systems Inc 432 Lakeside Dr 475 Oakmead Pky 900 S Winchester Blvd Sunnyvale CA 94086 Sunnyvale CA 94086 San Jose CA 95128 (408) 733-4200 (408) 733-0100 (408) 246-0461 Micropolis Corporation Shugart Technology Fujitsu America Inc 21329 Nordhoff St 340 EI Pueblo Road, Suite C 2945 Oakmead Village Ct Chatsworth CA 91311 Scotts Valley CA 95066 Santa Clara CA 95051 (213) 709-3300 (408) 438-6550 (408) 985-2300 New· World Computer Company Inc International Memories Inc 3176 Pullman St, Suite 119 10381 Bandley Dr Costa Mesa CA 92626 Cupertino CA 95014 (714) 556-9320 (408) 446-9779

146 August 1980 © BYTE Publications Inc