~ \~~1 ,,~~ ). . AUERBACH ON COMPUTER TECHNOLOGY This profile of RCA's new time sharing sys­ tem and other recent developments in the Spectra 70 line is extracted from a new 250- page analysis of the RCA Spectra 70 hard­ ware and· software in AUERBACH Standard EDP Reports, an analytical reference service published by AUERBACH Info, Inc., of Phila­ .delphia.

time sharing spectra 70 style

By J. BURT TOTARO Associate Editor,AUERBACH Standard EDP Reports AUERBACH CORPORATION

When the RCA Recognizing these problem of GE and IBM. RCA's apparent Spectra 70 se­ areas, RCA quietly set about clos­ intention is to remain competitive ries of comput­ ing the "facilities gap" between it­ in all areas of the small-to-me­ ers was an­ self and IBM. During the past year dium scale commercial computer nounced in De­ RCA has added new and impres­ market without enduring. the frus­ cember 1964, sive peripheral units to its Spectra trations of the more ambitious pio­ RCA entered 70 line and has greatly increased neers in the large-scale commercial head - to - head the capacity and scope of its soft­ time-sharing business. competition ware systems. Most recently, on The monthly rental .of an RCA with IBM and May 4, 1967, RCA announced the Spectra 70/46 Processor with 262,- its System 360. From the begin­ long-rumored Spectra 70/46 Time 144 bytes of core storage is $14,- ning, RCA promised to provide Sharing System, a development 125. RCA estimates that typical more computing power per dollar that serves to plug the only re­ 70/46 system configurations will than IBM. maining gap of any significance rent for between $25,000 and $30,-- Spectra 70 indeed offered much: in RcA's battle ~o match the proc­ 000 per month. Contributing to a family of five generally compati­ essing capabilities of IBM in the the relatively modest prices of ble computer systems, a high de­ small-to-medium-scale computer planned Spectra 70/46 systems are gree of source and object program market. the facts: (1) that the 262K-byte compatibility with the IBM Sys­ 70/46 Processor is basically an ex­ tem 360, extensive use of mono­ Spectra 70/46 panded version of the $11,125- lithic integrated circuitry, three The Spectra 70/46 Time Shar­ per-month Spectra 70/45 262K­ levels of integrated operated sys-. ing System includes a new Spectra byte Processor, (2) that only sin­ terns, and an extensive line of 70/46 central processor, a new 70/ gle-processor systems have been peripheral equipment. * But the 567 high~speed magnetic drum announced to date, and (3) that System 360 offered more~a great­ unit, and a specially-designed soft­ a maximum of 48 on-line remote er variety of hardware and, espe­ ware system called the Time Shar­ terminal units can be controlled cially, more "third generation" ing Operating System .(TSOS ). by the system. software facilities, such as ran­ Both hardware ~nd· software for According to its design goals, dom-access-oriented operating sys­ the Spectra 70 Time Sharing Sys­ the. Spectra 70/46 Time Sharing tems, source-language control of tem are scheduled for first delivery System will be an efficient batch random access devices, automatic during the third quarter of 1968. processing system with advanced data management systems, com­ The 70/46 marks RCA's entry multiprograming capabilities; re­ prehensive data communications into the time-sharing' computer mote, conversational time-shared control systems, and support of market, joining such competition operations in time-sliced mode will ~ime-shared processing. as the GE-645, IBM System 3601 be a powerful available facility Model 67, and SDS Sigma 7 com­ that may: in some installations, *For a detailed review of the Spectra 70· fam· puter systems. Howev~r, R~A has' consume only a limited amount of ily of computer systems, see "RCA Spectra 70 -A Compatible Competitor," by J. B. Totaro, designed its time-sharing system the system's total processing ca­ DataProce88ing Magazine, June 1966, pages 54-61. with more modest goals than those pacity. The more expensive GE- Reprinted From Data Processing Magazine July, 1967 645 and IBM System 360/Model same numbers). The few configu­ 70/46 Processor is its read-only 67 systems, by contrast, are de­ ration differences include the 70/ control memory unit. This unit signed primarily for time-shared 46's required use of a 70/567 has a memory cycle time of 480 processing. Drum Memory Unit and, if remote nanoseconds per 54-bit access. Noteworthy features of the 70/ terminals are expected to be used Read-only memory (ROM) is pro­ 46 Time Sharing System include: on-line, a nluLi-line communica­ vided in three banks, each of which • Hardware logic within the tions controller. Spectra 70/46 contains 2,048 54-bit words ( or processor to facilitate program systems are currently restricted to "Elementary Operations"). The paging and segmentation, provid­ the use of a single processor and Spectra 70/45 Processor, by con­ ing simultaneous system access 262K bytes of core storage. trast, provides only a single bank for up to 48 users at remote ter­ In addition to the 70/567 Drum of read-only memory, which is minals. Memory Unit, a minimum Spectra used exclusively for the emulation • Up to 2,097,152 bytes of vir­ 70/46 configuration will include of other computers, such as the tual memory available to program­ at least two 70/564 Disk Storage IBM 1401 or RCA 301. ers. Units and two magnetic tape units Spectra 70/46 systems cannot • A fast associative memory for for use by the system's software. use the emulation technique. Read­ translation of all virtual memory The 70/46 Time Sharing System only memory in 70/46 systems is addresses to real core storage ad­ is designed to take advantage of instead used to implement several dresses. the processing efficiencies made features that facilitate time-shared • A conversational FORTRAN possible through the use of a hier­ operation. The first bank of read­ IV compiler with interpretive exe­ archy of system storage devices only memory is used to provide cution capability. that range from magnetic tape the microprogramed routines that • F,IlI compatibility with the units to disks, drums, and finally will permit the 70/46 to operate systems programs and language to main core memory. in the Spectra 70/45 processing mode. The second bank is used to processors of the RCA Spectra 70 Storage general-purpose Tape Operating implement an address translation Spectra 70/46 magnetic core System (TOS) and Tape/Disc Op­ table (in a section called the memory is available in a single erating System (TDOS), both of Translation Memory), an interval block of 262,144 bytes. Memory which are used with Spectra 70/ timer, and other hardware features cycle time is 1.44 microseconds 35, 70/45, and 70/55 computer used by the 70/46 in its paging per 2-byte access. Each byte con­ systems. and time-sharing operations. A sists of eight data bits and one portion of the second bank and all Configurations parity bit. Bytes can be grouped of the third bank are used to im­ Spectra 70/46 system configura­ into 4-byte, 32-bit binary words. plement specialized functions, tions (and their costs) will closely This data structure is identical such as translation table manipu­ 1 approximate those of Spectra 70/ with that of the Spectra 70/35, lation, paging interrupt handling, 45 systems. Any Spectra 70 periph­ 70/45, and 70/55 systems (and, etc., that would normally be per­ eral device that can be used with therefore, with the IBM System formed by software. A special the 70/45 can also be used with 360). Spectra 70/46 processor instruc­ the 70/46 (and in generally the A major feature of the Spectra tion, Function Call, is provided to call for and execute these micro­ programmed routines. The new 70/567 Drum Memory Unit is currently offered for use exclusively with the 70/46 Time Sharing System. In this system, pages of user programs will be stored in on-line disk storage units, from which they will be called to main memory for execution. Once in main !Demory.. program pages that must be temporarily dumped to make room for higher-priority pages are sent to the Drum Mem­ ory Unit, where they await rapid retransmission to core when main memory space again becomes available., Also residing in the Drum Memory Unit will be the most frequently used control rou­ tines of the 70/46 Time Sharing DEBUGGING AT THE console of a prototype Spectra 70/46 Time Sharing System. Operating Syste·m (T·SOS).

JULY • 1967 AUERBACH The purpose of so fragmenting erand address from its virtual ad­ core storage and programs is to dress form to the corresponding permit a large number of programs real address that is relative to the Vital statistics on the new drum (or program segments) to reside current location of the page in core include a storage capacity that concurrently in core storage in a storage. Virtual-to-real address ranges between 4.1 and 16.4 mil­ manner that permits execution translation takes place automati­ lion bytes, an average access time control to be passed easily between cally in the Spectra 70/46 Proc­ of 8.6 milliseconds, and a peak the resident programs, either on essor, and generally without any data transfer rate of 333,333 bytes an interrupt basis or a time-slicing increase in instruction execution per second. basis. Thus, even modest-sized time. (Instruction execution times 70/46 Processor core memories can accommodate for the 70/46 Processor are gen­ The RCA Spectra 70/46 Proc­ the processing needs of a large erally equal to those of the 70/45 essor is basically a 70/45 Process­ number of users, since only a lim­ Processor. ) or with additional features to fa­ ited number of pages of each re­ When the Spectra 70/46 Proc­ cilitate time-shared operations. All quested program require use of essor is operating in the time-shar­ features of the 70/45 Processor core storage at anyone time. ing mode, 24-bit virtual addresses are also included in the 70/46. Program pages not immediately are translated to 18-bit real ad­ The principal features added to required for execution in a Spec­ dresses by means of an associative the 70/45 in designing the 70/46 tra 70/46 system are stored in ran­ table-lookup search through the Processor include: dom access secondary storage­ Translation Memory portion of • Two additional banks of read­ typically a 70/564 Disk Storage read-only memory. The 12 low­ only memory. Unit. When these program pages order bits (i.e., the "displacement" • Virtual-to-real address trans­ are called for execution, they are field) of the virtual address are lation logic. relocated by the Time Sharing Ex­ used intact as the 12 low-order bits • An interval timer with a 100- ecutive routine to any available of the real address. The next 11 microsecond resolution. page in core storage. If active resi­ bits of the virtual address repre­ • Hardware control of paging dent pages must be displaced by sent the segment and page num­ and segmentation. higher-priority program pages, ber of the program address. These • Interrupt capabilities for in­ they are temporarily dispatched to bits are translated via the Transla­ terval timer run-out, paging errors, the system drum unit, from which tion Memory to a 6-bit real page and page queuing. they can be quickly called and re­ address which is combined with • Six microprogramed operators instated in any available page of the untouched 12-bit displacement to control use of the translation core storage. field to form an 18-bit real address Memory, interval timer, and page The 512-word Translation Mem­ that is capable of directly address­ queuing. ory is used by the software when ing up to 262,144 bytes of core • Capacity to add up to four assigning and relocating program storage. high-speed selector I/O channels pages to specific blocks of core (as compared to a maximum of storage. The Translation Memory Processor Modes three medium-speed selector chan­ sets a limit of 512 pages as the Two processing modes are avail­ nels with the 70/45). maximum number of uniquely ad­ able for users of the 70/46 Time • Memory protection that in­ dressed program pages that any Sharing System. If a specific bit is cludes both Store and Fetch Pro­ program can contain. This means set in the processor's Interrupt tect features. The Spectra 70/46 that every Spectra 70/46 program Status Register and a correspond­ Processor has been designed to can be written as if 2,097,152 ing bit is set within the virtual facilitate serving multiple users bytes of core storage were avail­ address of an instruction or oper­ with multiple programs. To under­ able for its use, even though the and, automatic virtual-to-real ad­ stand this design, it is necessary actual core storage unit provides dress translation takes place and to consider the concept of paging. only 262,144 bytes of real storage. the various microprogramed oper­ The Spectra 70/46's provision of ations of the Function Call in­ Paging about two million bytes of virtual struction can be utilized. This The Spectra 70/46 core storage core storage could be expanded to processing .mode is called the 70/ unit is divided into many blocks eight million bytes without sub­ 46 or time-sharing mode. All user of equal size called "pages." The stantial hardware change, but RCA programs compiled by the Spectra basic page size is 4,096 bytes, but has not indicated that such an ex­ 70/46's Time Sharing Operating 2,048-byte page lengths can also pansion is forthcoming. System (TSOS) software include be specified through the software. virtual addresses with the trans­ Spectra 70/46 prograD)S are com­ Address Translation late bit set. piled in bloc~s of 4,096-byte pages, Before executing instructions in The other processing mode is and only a limited number of program pages that are dispersed called the 70/45 mode. In this pages of each program need be in randomly through core storage, the mode all object program addresses core storage at any given instant 70/46 Processor must translate are treated as direct addresses, of program execution. each non-I/O instruction and op- and no address translation occurs. DATA PROCESSING MAGAZINE It will be possible to execute all achieving program compatibility lector channel is 465,000 bytes per Spectra 70/45 object programs, with unlike computers bas been second. including the TOS and TDOS soft­ successfully accomplished by RCA ware control routines, in a Spectra and IBM, and is currently being Time-Sharing Software 70/46 Processor operating in the developed by several other manu­ To complement the prOmIsmg 70/45 mode, with results identical facturers. hardware design of the Spectra to those obtained in a 70/45 Proc­ 70/46, RCA has announced an essor. I/O Capacity impressive software package called Like the Spectra 70/45 system, the Time Sharing Operating Sys­ Instruction Set the 70/46 Time Sharing System tem. TSOS promises an efficient The Spectra 70/46 ProcessOl' in­ can concurrently execute one ma­ random-access-oriented multipro­ cludes the full instruction reper­ chine instruction, one input-output graming operating system plus ca­ toire of the Spectra 70/45 Proc­ operation on each of the installed pabilities for providing up to 48 essor, plus two new instructions; selector channels, and one data users at remote terminals with im­ Test and Set, and Function Call. transfer operation on each of the mediate, conversational access to The Test and Set instruction can eight subchannels included in the the central 70/46 computer. In­ be executed in either the 70/45 or standard multiplexor channel. Up cluded in the software package 70/46 mode. This instruction is to 256 low-speed I/O devices can will be a complete range of batch used for bit-testing anywhere in be connected to a 70/46 system and conversational language proc­ main memory. The Function Call via the multiplexor channel. essors, remote syntax checking, de­ and its several microprogramed Selector channels are optional bugging and file editing systems, operations ( called Special Func­ equipment, and two, three, or four an extensive data management tions) can be executed only in the such channels can be installed. system, and a powerful executive 70/46 processing mode, and an Each selector channel has two control program. RCA plans to de­ attempt to execute them in the trunks, permitting two I/O con­ liver the entire Time Sharing Op­ 70/45 mode results in an inter­ trol units to be connected. Input/ erating System during the third rupt. output data is transferred into and quarter of 1968. The purpose of the Special Func­ out of core storage in 2-byte blocks The nucleus of TSOS is its net­ tions is to reduce overhead times over the Selector Channels, and work of system control programs normally associated with time­ the 70/46 Processor is delayed a used in the "privileged" mode by sharing systems by implementing maximum of 1.44 microseconds the central Spectra 70 system. The in hardware (i.e., read-only mem­ for each block transferred. Thus, principal control programs in­ ory) functions which are usually the I/O throughput capacity of the clude: the resident Executive pro­ performed by relatively slow soft­ 70/46 system is 1.4 million bytes gram; the File Control Processor ware control routines. This ap­ per second. (The 70/45 Processor, (FCP) for catalog, file, and data proach to reducing the overhead by contrast, is delayed 1.44 micro­ management; an interactive data delays associated with software seconds for each single-byte I/O communications input-output sys­ operating systems has been widely transfer, resulting in an I/O tem; an interactive software de­ discussed but rarely used to date. throughput capacity. that is half bugging system; and hardware A similar use of read-only mem­ that of the 70/46.) The maximum diagnostic routines. ories to implement emulators for data rate possible over a single se- The chief components of the

RCA's NEW SPECTRA 70/552 Alphanumeric Video Data THE SPECTRA 70/630 Data Gathering System transmits Terminal provides keyboard input and CRT output facili· data from input stations such as this to a Spectra 70 com· ties. puter. JULY • 1967 AUERBACH maintains catalogs of all files in (i.e., single record) basis. The the system and provides facilities Text Editor should prove of great for indexed sequential access to value in maintaining symbolic pro­ Executive program will be the fol­ files stored on random access de­ grams and their associated data lowing: vices. Options available to the user files. The batch utility programs • Task Scheduler, to maintain a include the capability to specify include a sort/merge program, a single task queue from multiple file names and characteristics at file maintenance routine for sys­ input sources, including ,remote execution time rather than at as­ tem and user programs, and a terminals, and to schedule on a sembly or compilation time, and test data generator. priority basis the concurrent exe­ the capability to share files among All software comprising the cution of as many programs as users through the use of pass­ Time Sharing Operating System is the system resources will allow. words. currently scheduled for delivery The Task Scheduler will also in­ Also controlled by the FCP is during the third quarter of 1968. clude a time-sharing algorithm to the TSOS Data Management Sys­ In summary, the Time Sharing control responsive time-shared op­ tem. Two types of file organization Operating System and its many erations. are supported: sequential and in­ components represent RCA's an­ • Memory Manager, to control dexed sequential. The Data Man­ swer to the large-scale, random­ the dynamic allocation of program agement System provides facilities access-oriented software systems pages ~d to manage the use of for manipulating either type of file offered by IBM with its Operating the more than two million bytes by means of the· following func­ System 360 and the Model 67's of virtual storage available to the tions: describe, create, access copy, Time Sharing System. TSOS sup­ programmer. change, and delete. A file protec­ plants the long-discussed Disk Op­ • Device Allocator, to manage tion system prevents unauthorized erating System in the RCA Spectra the pool of input-output devices reading and writing of files in a 70 software line. Because TSOS available to the· system, and to as­ dynamic time-shared environment. includes not only time-sharing fa­ sign free I/O devices to the pro­ cilities, but also impressive multi­ grams' device-independent I/O Processing Programs programming and data manage­ requests. In addition to the network con­ ment facilities, it is likely that the • Peripheral Input-Output, to trol programs. TSOS provides a Spectra 70/46 Time Sharing Sys­ provide optional buffering of large set of processing programs tem (including TSOS) will prove punched-card input files and print­ available for use by the system attractive to some users whose er-destined output files on random and problem programmers. The processing requirements do not in­ access devices or magnetic tape TSOS processing programs include clude remote,. time-shared process­ units. language processors and utility or ing. • Job Control, to accept user­ service programs. Both the process­ specified Job Control Language ing programs and the users' pro­ Compatibility statements used to enter and de­ grams are executed in the "non­ The Spectra 70/46 Time Shar­ fine batch processing jobs at the privileged" mode under control of ing System is compatible with the central 70/46 computer center. the TSOS control programs. RCA Spectra 70/35, 70/45, and • Command Language Control, Language processors are sup­ 70/55· systems to the extent that to enable users at remote terminals plied in conversational and batch all instructions, character codes, to communicate with the central form. The conversational language interrupt faCilities, and special fea­ system in either conversational or processors include an interpretive tures available in the nontime­ batch mode. The Command Lan­ FORTRAN compiler that uses a sharing systems are also available guage is an extension of the Job FORTRAN subset language, and in the 70/46 system and function Control Language. It permits the syntax checking programs for in the same manner. Therefore, users at remote terminals to iden­ source-level FORTRAN, COBOL, when operating in the 70/45 mode, tify themselves, to specify the and assembly-language programs. the 70/46 system will be able to tasks the system is to perform, The more conventional language use the TOS and TDOS software and to monitor the execution of processors that operate in batch systems and execute object pro­ these tasks. Command Language mode are a FORTRAN IV com­ grams compiled for 70/35, 70/45, procedures can be prestored for piler, a COBOL compiler, a Macro and 70/55 systems, provided that efficiency of operatioq. Assembler, and a Report Program the programs are timing-independ­ Generator. ent and system optional features Data Management Utility programs are also pro-­ are identical. A major system control program vided in both conversational and Functioning in the 70/46 mode in the Time Sharing Operating batch modes. The two conversa­ under the specialized Time Shar­ System is the File Control Process­ tional service programs are the ing Operating System, the 70/46 or (FCP). The FCP provides com­ Desk Calculator and Text Editor will be able to compile all source prehensive file management and programs. Using the Text Editor, programs originally written to data management systems. In the the remote user can create, modify, function under TOS .or TDOS in area of file management, the FCP and display files on a line-at-a-time 70/35, 70/45, or 70/55 systems.

DATA PROCESSING MAGAZINE The Job Control Language (JCL) the system will provide a maxi­ New Hardware and Software used with the Spectra 70/46 Time mum response time of eight sec­ In addition to the 70/46 Time Sharing Operating System is an onds for each of 48 interactive re­ Sharing System, RCA has expand­ expanded version of JCL as used mote terminals, assuming that all ed and impx:oved its product line with the Tape and Tape/Disc Op­ terminals are concurrently· active in other areas during .the past erating Systems, but is not fully and that four background pra­ year. New hardware products in­ compatible With the latter. grams are also being processed clude a controller for Burroughs, Because of the high degree of concurrently. IBM, Qr NCR MICR sorter-readers, compatibility between the 70/46 The Spectra 70/46 hardware/ a high-speed ( 1,000 cps) paper and the general-purpose Spectra software combination as specified tape reader, "quietized" printers 70 computer systems, users of the is impressive and deserving of fur­ with 96-character sets, an im­ 70/35, 70/45, and 70/55 systems ther scrutiny by the industry as proved CRT display device, and 7- should be able to upgrade to the its implementation progresses. The track magnetic tape units that more advanced facilities of the 70/46 Time Sharing System is not provide tape compatibility with Time Sharing System with a mini­ startlingly revolutionary in its de­ earlier RCA 301 and 501 systems. mum of conversion-time difficulty. sign nor extravagantly bold in its More specialized hardware sys­ Like the RCA Spectra 70/35, goals (and, as such, may not ap­ tems of recent development are 70/45, and 70/55 systems, the peal to the industry's confirmed in­ the Spectra 70/510 Voice Response Spectra 70/46 in 70 / 45 mode is novators ). Yet, the 70/46 may System, which delivers recorded largely compatible (both in terms work. Jt appears to combine the human-voice responses to on-line of programs and data) with the better features of efficient multi­ inquirers at Bell System Touch­ general-purpose models of the IBM programing systems with ~ore ad­ Tone telephones, and the Spectra System·360 computers. vanced remote data communica­ 70/630 Data Gathering System (DGS), designed to gather infor­ Performance tions and time-sharing facilities. Its approach to time-sharing is evo­ mation at remote, point-or-transac­ A prototype Spectra 70/46 sys­ lutionary-a natural, continuous tion input stations (such as badge tem is currently operational and progression from .the time-tested readers, card readers, etc.) and being used by RCA for software batch processing facilities to those transmit it to a central Spectra 70 development, but no detailed per­ tJtat may be better suited to cope computer system. formance estimates are. available with the processing needs of the Software improvements have to date. As a preliminary· perform­ future. centered on adding random access ance indication, RCA states that device capabilities to the Spectra 70 language processors and ex­ Table 1. Profile of the RCA Spectra 70/46 Processor panding the support of data com­ Core storage cycle time, microseconds 1.44 munications devices. Also, the Bytes accessed per cycle 2 Spectra 70 Basic Time Sharing Sys­ Core storage capacity, bytes 262,144 tem (BTSS) is being developed. as an all-software approach to limited Selector channels 0,2,3, or 4 time-shared processing with Spec­ Multiplexor channels 1 tra 70/45 systems. By means of these develop­ Selector channel capacity, bytes per second 465,000 ments, RCA has improved its posi­ Multiplexor channel capacity, bytes per second 465,000 tion as a worthy competitor of IBM Maximum combined I/O data transfer rate, 1,388,888 in all areas of the small-ta-medium bytes per second scale computer market. RCA has Processor speeds, micros.econds* accomplished this feat with the aid of a maturing market and product Fixed-point binary planning philosophy that does not c=a+b 25.2 attempt to match in every detail c=aXb 81.9 the vast facilities of the IBM Sys­ Fixed-point decimal tem 360, but instead attempts to c=a+b 42.2 analyze the demands of the market c=aXb 127.0 place and to implement whatever Floating-point (short) facilities are required to remain c=a+b 37.4 competitive, but on a scale that is c=aXb 67.6 feasible and potentially profitable. Floating-point (long) The hardware and software de­ c=a+b 52.6 sign of the new Spectra 70/46 c=aXb 211.5 Time Shanng System is an excel­ lent case in point. *The fixed-point binary and short floating-point operations use 32-bit binary operan~s; long floatfng-pbint operations use 64-bit binary operands. The fixed-point decimal times are based on Biped 5-digit (3-byte) decimal operands.

JULY • 1967