DOCSLIB.ORG

Universal Serial Bus (USB)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Universal Serial Bus (USB) Universal Serial Bus (USB) The Universal Serial Bus is a cable bus that allows high- Mbits/sec or 12 Mbits/sec, over a maximum cable length speed data exchange between a host computer and a variety of 5 meters. USB cable contains 4 wires: of peripherals. Supporting both attachment and removal of peripherals while the host system is running, USB was ■ Two of the wires form a twisted pair, which is used for dif- designed to provide a convenient and universal interface for ferential data transmission connecting peripherals to desktop computers, without the ■ The remaining two wires provide power and ground for de- need to power down the computer. In this article Barbara vices that don’t have their own 5 V DC power supply. provides an introduction to the USB standard, outlining the goals of the USB committee and describes the physical USB device speeds cabling and connectors, the physical and logical bus topol- The USB specification classifies USB devices into two main ogies, the types of data transfers, and the communication flow types: between the different layers of USB software. ■ Low-speed devices ■ Full-speed devices he Universal Serial Bus (USB) was originally designed by a consortium of telecom companies and desktop PC Low-speed devices Tsuppliers, which included Compaq, DEC, IBM, Intel, Low-speed USB devices (typically switches, mice and joysticks, Microsoft, NEC and Northern Telecom. Their primary purpose and keyboards) transfer USB data at 1.5 Mbits/sec. The cost of for working together was to provide a computer-telephony these devices is kept down by the fact that their low-bandwidth connection mechanism. cables can be designed without shielding. However, the members soon realized that the USB was well Full-speed devices suited to many applications outside the area of computer- Full-speed USB devices (such as video, disk and LAN telephony integration. interfaces) transfer data at 12 Mbits/sec. As might be expected, these full-speed devices are designed for performance, and their The goals of the USB committee were threefold: support of this higher data transfer rate is more expensive. ■ To provide an architecture that could link desktop PCs to the telephone network USB usage in 1998 ■ To develop an architecture that truly offered an easy way for users to connect and reconfigure peripherals ■ To provide a means by which a large number of peripherals could be attached to desktop PCs, without the traditional tangle of cables and different I/O interface standards. USB The USB connectivity vision Despite the fact that USB is well defined, desktop computer suppliers won’t switch over to this new peripheral standard Mouse Printer Modem Video LAN immediately. Most vendors plan to take a phased approach, by providing one (or possibly two) USB ports on their desktop Keyboard Serial Audio SCSI system, while still providing the traditional PC I/O interface ports. (See Figure 1) This transitional phase will allow time for USB usage in 200X both hardware and software companies to prepare for the shift to the USB architecture. USB USB USB While there are several other competing I/O architectures, USB will probably become the dominant desktop I/O architecture for Keyboard Mouse several reasons. (See the sidebar entitled The competition on Video Printer page 54.) LAN Scanner Digital audio I/O The USB physical media Figure 1 Digital telephony USB supports up to 127 devices, with bandwidths of 1.5 Modem Reprinted from VMEbus Systems / June 1998 / 1 Copyright 1998 ~ All rights reserved Universal Serial Bus (USB) USB physical topology ■ self-powered hubs The USB architecture supports a hierarchical topology, where ■ low bus-powered devices “downstream” hubs and devices are connected to “upstream” ■ high bus-powered devices hubs (in a star-like pattern) with the restriction of a maximum ■ self-powered devices of 5 hubs along any given chain. Figure 2 shows the tiers in this hierarchy. Hubs are intelligent devices that not only act as signal DC power flows downstream from the root hub to the various repeaters and routers, but also provide some basic power hubs and peripherals [4]. The maximum power that any device management [3]. can draw from the upstream bus is 500 mA @ 5V, with an added The root hub (in the USB host controller) is the anchor point Host (Root Hub) for all of the USB ports in the system. Data flows between the Host (Root Tier) root hub and the USB devices through the signal lines and hubs Upstream of the hierarchy in 2 directions: Tier 1 Hub 1 ■ downstream, starting at the root hub, and flowing from hub Tier 2 to hub, until it ultimately flows into a peripheral device Node ■ upstream, starting from a peripheral device, and flowing Hub 2 Node from hub to hub, until it reaches the root hub Tier 3 Downstream Hub 3 Hub 4 Node Node USB power distribution Tier 4 Each USB hub or peripheral might have its own local power supply, or it might draw its power from the bus, through its upstream cable. USB devices can be classified into 5 categories, Node Node Node Node based on how they derive their power: ■ bus-powered hubs Figure 2 The competition There are several I/O architectures that are competing with Mbits/sec over a maximum cable length of 4 feet [1]. However, USB to provide peripheral interconnection to desktop GeoPort was designed strictly to support telephony devices computers, including: and applications, and has never been extended to support other types of devices outside of this category. [2]. ■ Apple Desktop Bus ■ Geoport Access.bus ■ Access.bus Access.bus uses: ■ Firewire (IEEE1394) ■ a hardware layer based on the Phillips I2C bus [8] Apple Desktop Bus ■ a software layer developed by Digital, to provide additional The Apple Desktop Bus (ADB) is a low-speed serial bus that functionality for I2C connects input devices, such as keyboards, mouse devices and graphics tablets to a Macintosh computer. ADB provides a I2C bus is an acronym for Inter-IC bus. That name explains its simple read/write protocol for up to 16 devices. ADB supports purpose, which is to provide a communication link between data rates of up to 90 Kbits/sec. Some disadvantages of ADB integrated circuits. This bus provides 2 active wires, and a single are its relatively low data rate, and the fact that it is not an ground connection. The active wires are the Serial Data line and entirely “open” standard because Apple Computer owns the Serial Clock line, which are both bi-directional [8]. patents on ADB. Access.bus is an extension of I2C that routes the Serial Data GeoPort and Serial Clock lines through cables, to support keyboards, GeoPort has historically been an Apple proprietary interface. mice, monitors and microcontrollers. It provides speeds up to However, Apple is currently licensing the GeoPort spec- 100 Kbits/sec, and the protocols provided by its software layer ification to other companies. Apple Computer developed this allow it to interconnect up to 127 I/O devices. It is royalty free, interface to enable Macintosh telephony applications, but cable lengths are very limited, and there are no lines in the including both voice and data. cable for distribution of DC power to devices. Apple’s GeoPort Telecom Adapter provides hardware and Firewire (IEEE1394) software that supports: Firewire (IEEE1394) supports up to 63 peripheral devices, and offers very high data transfer rates – from 100 Mbits/sec to 400 ■ data communications Mbits/sec. It provides ample bandwidth to support almost any ■ fax communications peripheral, and is well suited to I/O applications that require ■ telephony services such as voice mail very high-speed data transfers. However, its complexity (and its high cost) make it impractical as a desktop I/O interconnect The standard GeoPort uses RS-422 signaling, and provides a for low-performance, low-cost peripherals, such as mice and point-to-point link that supports data transfer rates up to 2 keyboards. [2] 2 / Reprinted from VMEbus Systems / June 1998 Copyright 1998 ~ All rights reserved restriction that the maximum current that it can draw during The logical USB architecture startup is 100 mA. Figure 4 shows the logical topology of the USB architecture shown in Figure 2. While the devices are physically attached to A self-powered hub can be designed with a power supply that the USB in a tiered, star topology, the details of this physical provides the maximum DC current (500 mA @ 5V) to each of hierarchy are hidden from the application program by the system its downstream ports. However, a bus-powered hub has only the software, which presents each logical device to the application DC power from the upstream cable (500 ma @ 5V) to distribute program as a collection of endpoints. The application program to all of its downstream ports. If several devices are connected can then exchange data directly with each endpoint. [1]. This to its downstream ports, the bus-powered hub might draw more logical connection to each device endpoint is represented by a than its allotted 500 mA. point-to-point line segment in Figure 4. To prevent damage to the DC power supplies, the host (root hub) Hub 1 and all self-powered hubs must have overcurrent protection on Node Node their DC power supplies. If any self-powered hub detects an Node Hub 4 aggregate current drawn by all downstream ports in excess of 5.0 Amps, its overcurrent protector removes power from all downstream ports, and it reports the condition to the host controller [1]. Hub 2 Application Node program USB cable connectors Some USB devices (such as keyboards, mice and hubs) have Node their upstream cable permanently attached to them.
Load more

Recommended publications
  • Single-Chip Geoport Transceiver Datasheet (Rev. B)
    SN75LBC776 SINGLE-CHIP GeoPort TRANSCEIVER SLLS221B – NOVEMBER 1995 – REVISED MARCH 2002 D Single-Chip Interface Solution for the DB or DW PACKAGE 9-terminal GeoPort Host (DTE) (TOP VIEW) D Designed to Operate up to 4 Mbit/s Full DA1 1 20 GND Duplex VEE 2 19 VCC D Single 5-V Supply Operation C– 3 18 DY1 D 6-kV ESD Protection on All Terminals C+ 4 17 RY3 5 16 D SHDN RB3 Backward compatible With AppleTalk and DZ2 6 15 RA2 LocalTalk DY2 7 14 RY2 D Combines Multiple Components into a GND 8 13 RB1 Single-chip Solution DEN 9 12 RA1 D Complements the SN75LBC777 9-Terminal DA2 10 11 RY1 GeoPort Peripheral (DCE) Interface Device D LinBiCMOS Process Technology description The SN75LBC776 is a low-power LinBiCMOS device that incorporates the drivers and receivers for a 9-pin GeoPort host interface. GeoPort combines hybrid EIA/TIA-422-B and EIA/TIA-423-B drivers and receivers to transmit data up to four megabits per second (Mbit/s) full duplex. GeoPort is a serial communications standard that is intended to replace the RS-232, Appletalk, and LocalTalk printer ports all in one connector in addition to providing real-time data transfer capability. It provides point-to-point connections between GeoPort-compatible devices with data transmission rates up to 4 Mbit/s full duplex and a hot-plug feature. Applications include connection to telephony, integrated services digital network (ISDN), digital sound and imaging, fax-data modems, and other serial and parallel connections. The GeoPort is backwardly compatible to both LocalTalk and AppleTalk.
    [Show full text]
  • Designing PCI Cards and Drivers for Power Macintosh Computers
    Designing PCI Cards and Drivers for Power Macintosh Computers Revised Edition Revised 3/26/99 Technical Publications © Apple Computer, Inc. 1999 Apple Computer, Inc. Adobe, Acrobat, and PostScript are Even though Apple has reviewed this © 1995, 1996 , 1999 Apple Computer, trademarks of Adobe Systems manual, APPLE MAKES NO Inc. All rights reserved. Incorporated or its subsidiaries and WARRANTY OR REPRESENTATION, EITHER EXPRESS OR IMPLIED, WITH No part of this publication may be may be registered in certain RESPECT TO THIS MANUAL, ITS reproduced, stored in a retrieval jurisdictions. QUALITY, ACCURACY, system, or transmitted, in any form America Online is a service mark of MERCHANTABILITY, OR FITNESS or by any means, mechanical, Quantum Computer Services, Inc. FOR A PARTICULAR PURPOSE. AS A electronic, photocopying, recording, Code Warrior is a trademark of RESULT, THIS MANUAL IS SOLD “AS or otherwise, without prior written Metrowerks. IS,” AND YOU, THE PURCHASER, ARE permission of Apple Computer, Inc., CompuServe is a registered ASSUMING THE ENTIRE RISK AS TO except to make a backup copy of any trademark of CompuServe, Inc. ITS QUALITY AND ACCURACY. documentation provided on Ethernet is a registered trademark of CD-ROM. IN NO EVENT WILL APPLE BE LIABLE Xerox Corporation. The Apple logo is a trademark of FOR DIRECT, INDIRECT, SPECIAL, FrameMaker is a registered Apple Computer, Inc. INCIDENTAL, OR CONSEQUENTIAL trademark of Frame Technology Use of the “keyboard” Apple logo DAMAGES RESULTING FROM ANY Corporation. (Option-Shift-K) for commercial DEFECT OR INACCURACY IN THIS purposes without the prior written Helvetica and Palatino are registered MANUAL, even if advised of the consent of Apple may constitute trademarks of Linotype-Hell AG possibility of such damages.
    [Show full text]
  • Macintosh Powerbook 100.Pdf
    Macintosh PowerBook 100 System Fact Sheet SYSTEM POWER PORTS ADB: 1 Introduced: October 1991 Max. Watts: 17 Video: none Discontinued: August 1992 Amps: 2.00 Floppy: HDI-20 Gestalt ID: 24 BTU Per Hour: 58.14 SCSI: HDI-30 Form Factor: PowerBook 100 Voltage Range: 100-240 GeoPort Connectors: none Weight (lbs.): 5.1 Freq'y Range (Hz): 50-60 Ethernet: none Dimensions (inches): 1.8 H x 11 W x 8.5 D Battery Type: PB100, lead acid Microphone Port Type: none Soft Power Printer Speaker Codename: Asahi, Derringer, Monitor Power Outlet Headphone Oder Number: Modem KB Article #: 8981, 8982 Airport Remote Control Support Discontinued 9/1/98 1 VIDEO Built-in Display: 9" supertwist LCD Maximum Color Bit-depth At: 512 640 640 640 800 832 1024 1152 1280 VRAM Speed: VRAM Needed: Video Configuration: x384 x400 x480 x8702 x600 x624 x768 x870 x1024 n/a built in built-in LCD screen n/a 1 n/a n/a n/a n/a n/a n/a n/a 1 1-bit = Black & White; 2-bit = 4 colors; 4-bit = 16 colors; 8-bit = 256 colors; 16-bit = Thousands; 24-bit = Millions 2 The maximum color depth listed for 640x870 is 8-bit, reflecting the capabilities of the Apple 15" Portrait Display. LOGIC BOARD MEMORY Main Processor: 68000, 16 MHz Memory on Logic Board: 2 MB PMMU: none Minimum RAM: 2 MB FPU: none Maximum RAM: 8 MB Data Path: 16-bit, 16 MHz RAM Slots: 1 PB1xx L1 Cache: none Minimum RAM Speed: 100 ns L2 Cache: none RAM Sizes: 2, 4, 6 MB Secondary Processor: none Install in Groups of: 1 Slots: modem Speech Recognition Supported Supported Macintosh System Software: SOFTWARE A/UX 1.0 NOS 1.11 ProDOS
    [Show full text]
  • Owner's Manual for Mac OS
    Warranty Registration: User Manual register online today for a chance to win a FREE Tripp Lite product—www.tripplite.com/warranty USB Serial Adapter for MAC OS 8.6 - 9.x (Software v 2.2) Model: USA-19HS Table of Contents • Introduction • Capabilities • Installation Instructions • Configuring Your Serial Device • Keyspan Serial Assistant • Problem Solving • Appendices • Frequently Asked Questions (FAQs) • Compatibility List for Mac OS • Configuration Examples for Mac OS • Serial Port Pin Outs • TX Ack Advance • Notices • Keyspan Warranty Information Note: This documentation applies to Keyspan's USB Serial Adapter Software for Mac OS 8.6 - 9.x and covers the features and use of this software on that platform. For Mac OS X information and instructions, please read the Keyspan USB Serial Software for Mac OS X User Manual or visit Keyspan's web page <http://www.keyspan.com>. This User Manual applies to the Keyspan USB Serial Adapter Software for Mac OS. Rev 03jul13 Page 1 Keyspan:USB Serial Adapter for Mac OS-v2.2 User Manual 1.1 - Introduction Looking for a way to connect a graphics tablet, modem, GPS receiver, or Palm Organizer to your USB equipped Macintosh computer? The Keyspan USB Serial Adapter is a simple, inexpensive, and reliable way to make the connection. The Adapter plugs into any USB port on your Mac. It provides one DB9 serial port which can be used to connect your Dt. Up to 8 Keyspan USB Serial Adapters may be installed on one CPU if desired. Requirements The Keyspan USB Serial Adapter Software for Mac OS requires the following: • Macintosh: • At least one available USB port • Mac OS 8.6 - 9.x Contents The Keyspan USB Serial Adapter package includes: • Keyspan USB Serial Adapter (USA-19H) • USB cable • Mac and Windows compatible CD with software and user manual This User Manual applies to the Keyspan USB Serial Adapter Software for Mac OS.
    [Show full text]
  • Power Macintosh 5400 Technical Information 1996.Pdf
    Specificalions for Power Macintosh 5400 series computers Technical Information Main unit Processor A PowerPC™ 603e processor with the following features: • 180 megahertz (MHz) processor clock • built-in floating point unit (FPU) • 40 MHz system bus • 32 kilobytes (K) internal cache ( 16K data, 16K instruction) Memory • 16 megabytes (MB) of dynamic random-access memory (DRAM), expandable to a maximum of 136 MB in two sockets. The main logic board has 8 MB of DRAM soldered to it, and an 8 MB DRAM DIMM is installed in one of the sockets. DRAM DIMMs installed later should be 64-bit wide, 168-pin fast-paged mode, with 70-nanosecond (ns) RAM access time or faster. • I MB of built-in video RAM • 4 MB of read-only memory (ROM) • 8K of nonvolatile parameter memory • One socket for an optional High Performance Module (256K Level 2 Cache) Internal disk drives The following drives were installed in your computer at the factory: • Apple SuperDrive 1.4 MB high-density floppy disk drive • Apple ATA (AT Attachment) hard disk drive, also known as an Integrated Device Electronics (IDE) hard disk drive • Tray-loading CD-ROM drive (5.25-inch, 1/2-height 8x-speed). Video Graphic modes supported Your Power Macintosh 5400 series computer can display the graphic modes listed in the following table. In addition, your computer can display video input in some modes. Resolution Color depth Vertical scan rate · Video lop~ supp,orted 640 x 480 16-bit 60 Hz and 67 Hz yes 800 x 600 16-bit 60 Hz yes, 8-bit or less color depth 800 x 600 8-bit 72 Hz no 832 x 624 8-bit 75 Hz yes Video output With the optional Apple External Video Connector kit, your computer can be connected to an Apple Video Presentation System or a liquid crystal display (LCD) panel.
    [Show full text]
  • Power Macintosh 9500 Series
    K Service Source Power Macintosh 9500 Series Power Macintosh 9500/120, 9500/132, 9500/150, 9500/180MP, and 9500/200 K Service Source Basics Power Macintosh 9500 Series Basics Overview - 1 Overview The Power Macintosh 9500 Series computers are based on the PowerPC 604 microprocessor and support the industry-standard PCI (Peripheral Component Interconnect) bus specification. These computers are the most flexible, expandable, and highest-performance systems from Apple to date. The microprocessor for the Power Macintosh 9500 Series computers is on separate plug-in card, which allows for easy upgrades. The Power Macintosh 9500 family includes five versions: the 9500/120, the 9500/132, the 9500/150, the 9500/180MP (multi-processor), and the 9500/200. Basics Overview - 2 Features of the Power Macintosh 9500 Series include • 120, 132, 150, 180 (multi-processor) or 200 MHz PowerPC 604 microprocessor card with built-in FPU • Six PCI expansion slots • 10 MB per second internal SCSI channel, 5 MB per second external SCSI channel • 512K Level 2 cache • DRAM expansion up to 1536 MB using 168-pin, 70 ns, 64-bit DIMMs • A PCI Apple Accelerated Graphics card included with some configurations (the Power Macintosh 9500 Series does not include on-board video support) • Built-in AAUI and 10BASE-T Ethernet • AppleCD™ 600i 4x or1200i 8x CD-ROM drive • CD-quality stereo sound in/out • Mac™ OS system software 7.5.2, 7.5.3, or 7.5.3 Revision 2 Basics Configurations - 3 Configurations The Power Macintosh 9500/120 comes standard with • 120 MHz PowerPC 604 processor
    [Show full text]
  • USB Converter MT606 Series
    USB Converter MT606 Series FEATURES: Use with Keyboard Wedge Scanners Use with Keyboard and Mouse PS/2 and MAC-ADB Port Powered by PC or MAC Connect/Disconnect Without Reboot Plug and Play No Software Needed DESCRIPTION: The MT606 Series USB Converters provide an easy solution for converting existing peripherals, such as keyboards, pointing devices and barcode scanners, to Universal Serial Bus. Models are available to work with both PS/2 and Macintosh devices. As with all USB devices, the converter can be connected and disconnected without re-booting or powering down the computer. Each model has two ports. The MT606-4 has one PS/2 port and one Macintosh ADB (Apple Desktop Bus) port. The MT606-1 has one PS/2 keyboard port and one PS/2 Mouse port. TYPICAL APPLICATIONS: The MT606 converter will enable keyboards, pointing devices (mouse, trackball), and conventional barcode scanners with keyboard wedge interfaces, to be used with computers that feature the newer Universal Serial BUS. At present, newer PCs with the Windows® 98 and Windows 2000 operating systems, feature USB Ports. The Apple iMac, iBook, G3 and G4 use Universal Serial Bus for interfacing to external devices. The Model MT606-1 can accept inputs from a PS/2 Pointing Device and a PS/2 Keyboard or Barcode Scanner. The MT606-4 can accept inputs from a PS/2 keyboard or barcode scanner and any Macintosh ADB device, including Keyboard, Pointing Device or Barcode Scanner. SPECIFICATIONS: Dimensions: 2.2" X 1.5" X 0.85" Operating Voltage: 5VDC derived from USB 56mm X 40mm X 22mm connector.
    [Show full text]
  • Powerbook G3 Series 12.1" (233, 250 Mhz)
    PowerBookPowerBook G3G3 SeriesSeries 12.1"12.1" ((233233,, 250250 MHzMHz)) System Fact Sheet SYSTEM POWER PORTS ADB: 1 Introduced: May 1998 Max. Watts: 45 Video: HDI-15 Discontinued: August 1998 Amps: 1.2 Floppy: none Gestalt ID: 314 BTU Per Hour: 153.9 SCSI: HDI-30 Form Factor: PowerBook G3 Series Voltage Range: 100-240 GeoPort Connectors: 1 Weight (lbs.): 7.2 Freq'y Range (Hz): 50-60 Ethernet: 10Base-T Dimensions (inches): 2 H x 12.7 W x 10.4 D Battery Type: 49 WH Lithium Ion Microphone Port Type: PlainTalk Soft Power Printer Speaker Codename: Main Street, Wall Street Monitor Power Outlet Headphone Oder Number: M6359LL/A (233) Modem KB Article #: 24469, 24604 Airport Remote Control Family Model #M4753 24-bit video output port Weight includes modem, battery and SCSI port for connecting up to 7 devices CD-ROM module 1 VIDEO Built-in Display: 12.1" (diagonal) SVGA STN passive-matrix Maximum Color Bit-depth At: 512 640 640 640 800 832 1024 1152 1280 VRAM Speed: VRAM Needed: Video Configuration: x384 x400 x480 x8702 x600 x624 x768 x870 x1024 n/a built-in built-in LCD (2MB VRAM) n/a n/a n/a n/a 16 n/a n/a n/a n/a 1 1-bit = Black & White; 2-bit = 4 colors; 4-bit = 16 colors; 8-bit = 256 colors; 16-bit = Thousands; 24-bit = Millions 2 The maximum color depth listed for 640x870 is 8-bit, reflecting the capabilities of the Apple 15" Portrait Display. LOGIC BOARD MEMORY Main Processor: G3, 233/250 Memory on Logic Board: none PMMU: integrated Minimum RAM: 32 MB FPU: integrated Maximum RAM: 192 MB Data Path: 64-bit, 66/83 MHz RAM Slots: 2 144-pin
    [Show full text]
  • Apple Logic Board Design LPX-40
    Developer Note Apple Logic Board Design LPX-40 Developer Note © Apple Computer, Inc. 1996 Apple Computer, Inc. © 1996 Apple Computer, Inc. LIMITED WARRANTY ON MEDIA AND All rights reserved. REPLACEMENT No part of this publication may be If you discover physical defects in the reproduced, stored in a retrieval manual or in the media on which a software system, or transmitted, in any form or product is distributed, ADC will replace the by any means, mechanical, electronic, media or manual at no charge to you photocopying, recording, or otherwise, provided you return the item to be replaced without prior written permission of with proof of purchase to ADC. Apple Computer, Inc., except to make a backup copy of any documentation ALL IMPLIED WARRANTIES ON THIS provided on CD-ROM. Printed in the MANUAL, INCLUDING IMPLIED United States of America. WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR The Apple logo is a trademark of PURPOSE, ARE LIMITED IN DURATION Apple Computer, Inc. TO NINETY (90) DAYS FROM THE DATE Use of the “keyboard” Apple logo OF THE ORIGINAL RETAIL PURCHASE (Option-Shift-K) for commercial OF THIS PRODUCT. purposes without the prior written consent of Apple may constitute Even though Apple has reviewed this trademark infringement and unfair manual, APPLE MAKES NO WARRANTY competition in violation of federal and OR REPRESENTATION, EITHER EXPRESS state laws. OR IMPLIED, WITH RESPECT TO THIS No licenses, express or implied, are MANUAL, ITS QUALITY, ACCURACY, granted with respect to any of the MERCHANTABILITY, OR FITNESS FOR A technology described in this book. PARTICULAR PURPOSE.
    [Show full text]
  • The Powerpc Macs: Model by Model
    Chapter 13 The PowerPC Macs: Model by Model IN THIS CHAPTER: I The PowerPC chip I The specs for every desktop and portable PowerPC model I What the model numbers mean I Mac clones, PPCP, and the future of PowerPC In March 1994, Apple introduced a completely new breed of Mac — the Power Macintosh. After more than a decade of building Macs around the Motorola 68000, 68020, 68030, and 68040 chips, Apple shifted to a much faster, more powerful microprocessor — the PowerPC chip. From the start, Apple made it clear it was deadly serious about getting these Power Macs into the world; the prices on the original models were low, and prices on the second-generation Power Macs dropped lower still. A well- equipped Power Mac 8500, running at 180 MHz, with 32MB of RAM, a 2 GB hard drive, and a eight-speed CD-ROM drive costs about $500 less than the original Mac SE/30! When the Power Macs were first released, Apple promised that all future Mac models would be based on the PowerPC chip. Although that didn’t immediately prove to be the case — the PowerBook 500 series, the PowerBook 190, and the Quadra 630 series were among the 68040-based machines released after the Power Macs — by the fall of 1996, Macs with four-digit model numbers (PowerPC-based Power Macs, LCs, PowerBooks, and Performas) were the only computers still in production. In less than two years, 429 430 Part II: Secrets of the Machine the Power Mac line has grown to over 45 models.
    [Show full text]
  • Table of Contents Feature Article
    RLG DigiNews: Volume 4, Number 3 Table of Contents ● Feature Article ❍ Keeping Memory Alive: Practices for Preserving Digital Content at the National Digital Library Program of the Library of Congress by Caroline R. Arms ● Technical Feature ❍ Risk Management of Digital Information: a File Format Investigation ● Highlighted Web Site - TechFest ● FAQ - SCSI, UDMA, USB, and Firewire Technology ● Calendar of Events ● Announcements ● RLG News ● Hotlinks Included in This Issue Feature Article Keeping Memory Alive: Practices for Preserving Digital Content at the National Digital Library Program of the Library of Congress by Caroline R. Arms, National Digital Library Program & Information Technology Services, Library of Congress [email protected] Introduction The National Digital Library Program (NDLP) provides remote public access to unique collections of Americana held by the Library of Congress through American Memory. During the 1990s, the program digitized materials from a wide variety of original sources, including pictorial and textual materials, audio, http://www.rlg.org/preserv/diginews/diginews4-3.html (1 of 24)6/21/2005 1:31:04 PM RLG DigiNews: Volume 4, Number 3 video, maps, atlases, and sheet music. Monographs and serials comprise a very small proportion of the textual materials converted. The program's emphasis has been on enhancing access. No digitization has been conducted with the intent of replacing the original materials; indeed, great care is taken over handling fragile and unique resources and conservation steps often precede scanning. (1) Nevertheless, these digital resources represent a significant investment, and the Library is concerned that they continue to be usable over the long term. The practices described here should not be seen as policies of the Library of Congress; nor are they suggested as best practices in any absolute sense.
    [Show full text]
  • Theory of Operation Power Macintosh
    K Service Source Theory of Operation Power Macintosh Theory of Operation Introduction - 1 Introduction This section contains information about how the Power Macintosh operates. The Power Macintosh components work together to provide these general functions: • Central processing and control • Memory • Input/output (I/O) • Video and sound As you read this section, refer to the Power Macintosh Block Diagram, which shows the relationship of the components in Power Macintosh computers. Theory of Operation Introduction - 2 Specific functions of Power Macintosh components are covered in sections about • Power supply • Apple SuperDrive • SCSI hard drive • Internal mass storage devices • Main logic board • Expansion cards • System startup sequence Theory of Operation Central Processing and Control - 3 Central Processing and Control Processing and control logic in all Power Macintosh models are handled by the central processing unit (CPU) with the built-in math coprocessor and digital signal processor (DSP). Additional control signals are generated by the high- speed memory controller (HMC), Apple Memory Mapped I/O Controller (AMIC), and other components. The Squidlet Chip provides the system clocks. Theory of Operation Central Processing and Control - 4 CPU The main processor in the Power Macintosh computers is a PowerPC 601 microprocessor. Features of the PowerPC 601 microprocessor include • Full reduced instruction set computing (RISC) processing architecture • Parallel integer and floating-point processing units • An internal memory management unit (MMU) • 32 Kbits of on-chip cache memory The PowerPC 601 is a 32-bit address bus and a 64-bit data bus microprocessor. Theory of Operation Central Processing and Control - 5 FPU The PowerPC 601 includes a floating-point unit (FPU).
    [Show full text]