DOCSLIB.ORG

CALIFORNIA STATE UNIVERSITY, NORTHRIDGE RAM-DISK a Thesis

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
CALIFORNIA STATE UNIVERSITY, NORTHRIDGE RAM-DISK a Thesis CALIFORNIA STATE UNIVERSITY, NORTHRIDGE RAM-DISK A thesis submitted in partial satisfaction of the requirements for the degree of Master of Science in Engineering by Chung Ting Ho May, 1984 The Thesis of Chung Ting Ho is approved : Pr . John T. Jo , Cha1r California State University, Northridge ii TABLE OF CONTENTS Page Abstract : vi Chapter 1 DESIGN PHILOSOPHY AND THEORY 1 1.1 Overview l 1.2 : Design Background 4 1.3 Design Goal and Theory 7 Chapter 2 THEORY OF OPERATION 10 2.1 : System Monitor 10 2.2 : Operating System 12 2.3 : Custom Basic I/0 System for RAM-Disk 18 2.4 Description of The Block Diagram 22 Chapter 3 CIRCUIT DESCRIPTION 27 3.1 4146 Memory Chip 27 3.2 Z80A CPU 30 3.3 Detailed Circuit Description 34 3.4 Power Supply 41 Chapter 4 SOFTWARE DESCRIPTION 43 4.1 Self-Test Program 43 4.2 : Forrnating The RAM-Disk 44 4.3 : Custom Basic Input/Output System 45 Chapter 5 EVALUATION AND CONCLUSION 48 5.1 User Interface 48 5.2 : Performance Evaluation 49 5.3 : Conclusion and Comment 51 iii References 53 Appendix A CIRCUIT SCHEMATICS 54 Appendix B IC LISTING AND POWER REQUIREMENTS 58 Appendix c : SELF-TEST PROGRAM LISTING 59 Appendix D FORMATING PROGRAM LISTING 65 Appendix E MOVE PROGRAM LISTING 66 Appendix F CUSTOM BIOS DRIVE A PROGRAM LISTING 67 Appendix G CUSTOM BIOS DRIVE E PROGRAM LISTING 78 Figure 1 A MICRO-COMPUTER SYSTEM 1 Figure 2 A MOTHER-DAUGHTER RAM-DISK BOARD 8 Figure 3 : RAM-DISK BLOCK DIAGRAM 23 Figure 4 RAM-DISK INTERFACE FUNCTIONAL BLOCK DIAGRAM 26 Figure 5 4164 DYNAMIC RAM READ CYCLE TIMING 28 Figure 6 : 4164 DYNAMIC RAM WRITE CYCLE TIMING 29 Figure 7 4164 DYNAMIC RAM REFRESH CYCLE TIMING 30 Figure 8 ~ Z80 INSTRUCTION OPCODE FETCH TIMING 31 Figure 9 Z80 256-CYCLE REFRESH CONVERSION DIAGRAM 32 Figure 10 Z80 INPUT AND OUTPUT CYCLES TIMING 34 Figure 11 RAM-DISK COMPOSITE TIMING 39 Figure 12 MOVE PROGRAM FUNCTIONAL DIAGRAM 47 Table 1 RELATIONSHIP BETWEEN BLS, BSH AND BLM 16 Table 2 RELATIONSHIP BETWEEN BLS, MAXIMUM DISK SIZE AND EXTEND MASK 16 Table 3 RELATIONSHIP BETWEEN BLS, DIRECTORY ENTRY AND ALO, ALl 17 iv " ' Table 4 : RAM-DISK PARAMETER HEADER 20 Table 5 : RAM-DISK PARAMETER BLOCK 21 Table 6 : RAM-DISK BENCH MARK TEST so v ABSTRACT RAM-DISK by CHUNG T. HO Master of Science in Engineering Microcomputers are found in all areas of modern society. They have become the basic tools for word processing and data file management. A floppy disk drive is necessary for both long term file storage and on-line data support. Since the floppy disk drive is mainly a mechanical device, it is inherently slow. To improve the microcomputer's run-time efficiency, an alternate form of on-line data support is proposed. A RAM-disk is a block of solid state memory. When integrated into the microcomputer system, it functions just like a floppy disk. THE RAM-disk is completely transparent to the user. It is accessed in the same manner as a floppy disk, but its response speed is ten to twenty vi times faster than a floppy disk drive. The RAM-disk has 256K bytes of storage capacity. To simplify the hardware design, it is subdivided into eight tracks with 256 sectors per track and 128 bytes per sector. Several programs were created to integrate the RAM­ disk with computer. A format program is to initialize the RAM-disk. Two custom BIOS programs are to integrate the RAM-disk into either drive 'A' or drive 'E' of the computer system. Once the RAM-disk is formated and integrated into the system it is accessed as either drive 'A' or drive 'E' of the system. vii CHAPTER 1 DESIGN PHILOSOPHY AND THEORY 1.1 OVERVIEW In today's business and hobby world the micro-computer has become increasingly popular. The usual time consuming and laborious chores such as personal financing, inventory control and accounting can be taken over by a micro- computer which performs with much higher precision and greater speed. There are hundreds of different micro- computers on the market now, and there are just as many application software packages available. A micro-computer system generally consists of a CPU unit, a display such as TV screen or CRT monitor, a keyboard, a printer and at least one 5-1/4 or 8 inch floppy disk drive. : CRT . : PRINTER . ----------: CPU :---------- ----------: UNIT :----------. : 'KEYBOARD . : DIS'K DRIVES : FIGURE 1 A MICRO-COMPUTER SYSTEM The CPU unit includes the micro processor, timing circuitry, I/O control and on-line memory. For most 8-bit micro-processors such as the Z80, I8080 and M6502, there 1 2 are only 16 memory address bits available, which limits the maximum addressable on-line memory to 64k bytes. After the memory space reserved for the system monitor and the operating system software is subtracted, there are less than 60K bytes of memory available for the application program and data. In the early days of micro-computer history, very rarely would a program exceed 16K bytes in length, but as more software development tools became available, many complicated programs were developed. Application programs such as high level language compilers, spread sheet programs and word processor programs are extremely large and can not fit into the available memory space in its entirety. Therefore, they are broken down into smaller pieces as overlays. These overlays are stored in an off­ line mass storage device such as a floppy disk. As the program is being executed, each overlay is swapped in and out of the on-line memory as they are needed. It is the same with the data base programs. It is not unusual to have inventory data, accounting data or graphic data which are too large for the on-line memory space. They are broken down into smaller pieces so they can be loaded into the memory as they are processed by the computer. As the program becomes more complicated the more overlays it must create. For example, 'QUAD' a sophisticated business software which can perform inventory control, customer mailing list, payroll and many 3 other accounting functions has 17 overlays and the whole program takes 242K bytes of memory. To run such a program the overlays are swapped in and out of memory constantly, and the disk drive is being accessed almost continuously. In the past few years the floppy disk drive has became a vital part of any computer system for both long term program storage or run time program support such as over­ lays or library funtions storage. The floppy disk drive is interfaced to the CPU through a disk controller chip. The disk controller takes the CPU's parallel data bits and shifts them out serially to the disk drive during a disk write operation. Likewise, it shifts in the serial disk data bits and passes them to the CPU as 8-bit parallel data during a read operation. Due to this serial data link, the floppy disk data transfer rate is inherently slow and is limited to about 30 kilo-bytes per second. When the disk files are accessed randomly, there is an additional delay associated with the movement of the read/write arm, load/unload of the head and settling time. For a typical disk drive, the average random access time is 91 milli-seconds plus the head loading time of 35 milli-seconds. It takes 1.126 seconds to read a 30 kilo- byte long file from the disk if the file occupied one contiguous block on the disk. If the same file is broken up into 30 blocks of one kilo-bytes each, then the transfer time increases to 4.78 seconds. 4 A disk drive requires three levels of power supplies, a plus five volts for the TTL circuitry, a plus 24 volts for the stepping motor and 120 volts AC for the rotation motor. 1.2 DESIGN BACKGROUND In the past two to three years, several alternate forms of data storage methods have been developed to overcome the micro-computer's limitation of on-line memory space and slow floppy disk interface. One is the hard disk drive system such as Winchester disk drive. The hard disk technology has just been introduced into micro­ computer systems in the past two years. A typical Winchester hard disk drive has between one and twenty mega-bytes of storage capacity. It is generally used as an off-line storage device. Its data transmission rate is several times faster than a floppy disk drive, but the cost of a hard disk drive system and its controller electronics is usually higher than most people care to pay for it. Another method to increase on-line storage is done with the bank-switching memory. Bank switching is to have two or more banks of solid state memory. Each bank has the same storage capacity and can be switched in or out of the computer address range by some predetermined bits of a dedicated I/O port. A long program can be loaded into several consecutive banks of memory. During execution, the appropriate program segment is accessed by 5 the computer as each memory bank is addressed. The bank switching method has all the advantages of a solid state memory such as speed and reliability, and it can be expanded to more than two thousand banks of 64K bytes each. The disadvantages of the bank switching are that it requires special software to operate and it is difficult to implement as an add on feature.
Load more

Recommended publications
  • Section 10 Flash Technology
    10 FLASH TECHNOLOGY Overview Flash memory technology is a mix of EPROM and EEPROM technologies. The term “flash” was chosen because a large chunk of memory could be erased at one time. The name, therefore, distinguishes flash devices from EEPROMs, where each byte is erased individually. Flash memory technology is today a mature technology. Flash memory is a strong com- petitor to other memories such as EPROMs, EEPROMs, and to some DRAM applications. Figure 10-1 shows the density comparison of a flash versus other memories. 64M 16M 4M DRAM/EPROM 1M SRAM/EEPROM Density 256K Flash 64K 1980 1982 1984 1986 1988 1990 1992 1994 1996 Year Source: Intel/ICE, "Memory 1996" 18613A Figure 10-1. Flash Density Versus Other Memory How the Device Works The elementary flash cell consists of one transistor with a floating gate, similar to an EPROM cell. However, technology and geometry differences between flash devices and EPROMs exist. In particular, the gate oxide between the silicon and the floating gate is thinner for flash technology. It is similar to the tunnel oxide of an EEPROM. Source and INTEGRATED CIRCUIT ENGINEERING CORPORATION 10-1 Flash Technology drain diffusions are also different. Figure 10-2 shows a comparison between a flash cell and an EPROM cell with the same technology complexity. Due to thinner gate oxide, the flash device will be more difficult to process. CMOS Flash Cell CMOS EPROM Cell Mag. 10,000x Mag. 10,000x Flash Memory Cell – Larger transistor – Thinner floating gate – Thinner oxide (100-200Å) Photos by ICE 17561A Figure 10-2.
    [Show full text]
  • Sensors: Sensing and Data Acquisidon
    Sensors: Sensing and Data Acquisi3on Prof. Yan Luo For UMass Lowell 16.480/552 Sensors: Sensing and Data Acquisi3on 1 Prof. Yan Luo, UMass Lowell Outline • Sensors • Sensor interfacing • Sensor data conversion and acquisi3on • PIC microcontroller programming • Lab 1: Sensor design and data acquisi3on (a light intensity sensor) Sensors: Sensing and Data Acquisi3on 2 Prof. Yan Luo, UMass Lowell Basic Principle of Sensors • Transducer: a device that converts energy from one form to another • Sensor: converts a physical parameter to an electric output – Electric output is desirable as it enables further signal processing. • Actuator: coverts an electric signal to a physical output Sensors: Sensing and Data Acquisi3on 3 Prof. Yan Luo, UMass Lowell Sensors • Cameras • Analog sensors • Accelerometer - Con3nuously varying output • Rate gyro • Digital sensors • Strain gauge - on/off • Microphone - Pulse trains (freq convey measurement) • Magnetometer • Chemical sensors • Op3cal sensors Sensors: Sensing and Data Acquisi3on 4 Prof. Yan Luo, UMass Lowell Example: Photoresistor • Or Light Dependent Resistor (LDR) – Resistance decreases with increasing light intensity – Made of semiconductor – Photons absorbed cause electrons to jump into conduc3on band Sensors: Sensing and Data Acquisi3on 5 Prof. Yan Luo, UMass Lowell Interfacing with Sensors • Interface circuitry • ADC • Interfaces of the embedded system • SoVware drivers and APIs Sensors: Sensing and Data Acquisi3on 6 Prof. Yan Luo, UMass Lowell Example voltage divider circuit Vcc R2 V=Vcc x R1/(R1+R2) V R1 Sensors: Sensing and Data Acquisi3on 7 Prof. Yan Luo, UMass Lowell Analog-Digital Converter (ADC) • Types of ADC – Integrang ADC • Internal voltage controlled oscillator • slow – Successive approximaon ADC • Digital code driving the analog reference voltage – Flash ADC • A bank of comparators • Fast Sensors: Sensing and Data Acquisi3on 8 Prof.
    [Show full text]
  • Storage Systems and Technologies - Jai Menon and Clodoaldo Barrera
    INFORMATION TECHNOLOGY AND COMMUNICATIONS RESOURCES FOR SUSTAINABLE DEVELOPMENT - Storage Systems and Technologies - Jai Menon and Clodoaldo Barrera STORAGE SYSTEMS AND TECHNOLOGIES Jai Menon IBM Academy of Technology, San Jose, CA, USA Clodoaldo Barrera IBM Systems Group, San Jose, CA, USA Keywords: Storage Systems, Hard disk drives, Tape Drives, Optical Drives, RAID, Storage Area Networks, Backup, Archive, Network Attached Storage, Copy Services, Disk Caching, Fiber Channel, Storage Switch, Storage Controllers, Disk subsystems, Information Lifecycle Management, NFS, CIFS, Storage Class Memories, Phase Change Memory, Flash Memory, SCSI, Caching, Non-Volatile Memory, Remote Copy, Storage Virtualization, Data De-duplication, File Systems, Archival Storage, Storage Software, Holographic Storage, Storage Class Memory, Long-Term data preservation Contents 1. Introduction 2. Storage devices 2.1. Storage Device Industry Overview 2.2. Hard Disk Drives 2.3. Digital Tape Drives 2.4. Optical Storage 2.5. Emerging Storage Technologies 2.5.1. Holographic Storage 2.5.2. Flash Storage 2.5.3. Storage Class Memories 3. Block Storage Systems 3.1. Storage System Functions – Current 3.2. Storage System Functions - Emerging 4. File and Archive Storage Systems 4.1. Network Attached Storage 4.2. Archive Storage Systems 5. Storage Networks 5.1. SAN Fabrics 5.2. IP FabricsUNESCO – EOLSS 5.3. Converged Networking 6. Storage SoftwareSAMPLE CHAPTERS 6.1. Data Backup 6.2. Data Archive 6.3. Information Lifecycle Management 6.4. Disaster Protection 7. Concluding Remarks Acknowledgements Glossary Bibliography Biographical Sketches ©Encyclopedia of Life Support Systems (EOLSS) INFORMATION TECHNOLOGY AND COMMUNICATIONS RESOURCES FOR SUSTAINABLE DEVELOPMENT - Storage Systems and Technologies - Jai Menon and Clodoaldo Barrera Summary Our world is increasingly becoming a data-centric world.
    [Show full text]
  • "Firefly" Z80 General-Purpose Retro Computing Platform
    "FIREFLY" Z80 GENERAL-PURPOSE RETRO COMPUTING PLATFORM THREE FARTHING LABS http://www.threefarthing.com Page 1 of 13 PREFACE A project has to have a name and this one wound up being called "Firefly" as it©s the culmination of a wirewrap board begun several years ago while binge-watching the series of the same name. That board, in turn, was a redesign of a single board computer I created in 1998, creatively named the "SBCZ1." All three of these projects were begun as a chance to tinker with a processor I first met hands- on in 1984, the ZiLOG Z-80, though it was long-established by that time and dominated the business computer market. It was the CPU of preference behind most CP/M machines and CP/M was what I wanted to tinker with again, from the ground up ± not in some cozy emulator. When I began preparing to design the board I looked around on the Internet and found many excellent Z80 projects, including kit options. The choice was made to "roll my own" for numerous reasons. In the SBCZ1 I had most of a good design and wanted to retain a lot of hard work (done before I had Internet access, mind you). There were also specific reasons for wanting "to stay within ZiLOG canon" and work with a particular hardware configuration. I saw no kits that did just what I wanted in the way that I wanted. There was also a desire to maintain modularity and be extensible but not require a proliferation of modules for what I considered core functionality, yet great restraint was employed to keep "core functionality" spartan.
    [Show full text]
  • Use External Storage Devices Like Pen Drives, Cds, and Dvds
    External Intel® Learn Easy Steps Activity Card Storage Devices Using external storage devices like Pen Drives, CDs, and DVDs loading Videos Since the advent of computers, there has been a need to transfer data between devices and/or store them permanently. You may want to look at a file that you have created or an image that you have taken today one year later. For this it has to be stored somewhere securely. Similarly, you may want to give a document you have created or a digital picture you have taken to someone you know. There are many ways of doing this – online and offline. While online data transfer or storage requires the use of Internet, offline storage can be managed with minimum resources. The only requirement in this case would be a storage device. Earlier data storage devices used to mainly be Floppy drives which had a small storage space. However, with the development of computer technology, we today have pen drives, CD/DVD devices and other removable media to store and transfer data. With these, you store/save/copy files and folders containing data, pictures, videos, audio, etc. from your computer and even transfer them to another computer. They are called secondary storage devices. To access the data stored in these devices, you have to attach them to a computer and access the stored data. Some of the examples of external storage devices are- Pen drives, CDs, and DVDs. Introduction to Pen Drive/CD/DVD A pen drive is a small self-powered drive that connects to a computer directly through a USB port.
    [Show full text]
  • Efficient Automated Code Partitioning for Microcontrollers with Switchable
    Efficient Automated Code Partitioning for Microcontrollers with Switchable Memory Banks MICHAL CISZEWSKI and KONRAD IWANICKI, University of Warsaw 114 Switching active memory banks at runtime allows a processor with a narrow address bus to access memory that exceeds ranges normally addressable via the bus. Switching code memory banks is regaining interest in microcontrollers for the Internet of Things (IoT), which have to run continuously growing software, while at the same time consuming ultra-small amounts of energy. To make use of bank switching, such software has to be partitioned among the available banks and augmented with bank-switching instructions. In contrast to the augmenting, which is done automatically by a compiler, today the partitioning is normally done manually by programmers. However, since IoT software is cross-compiled on much more powerful machines than its target microcontrollers, it becomes possible to partition it automatically during compilation. In this article, we thus study the problem of partitioning program code among banks such that the resulting runtime performance of the program is maximized. We prove that the problem is NP-hard and propose a heuristic algorithm with a low complexity, so that it enables fast compilation, and hence interactive software development. The algorithm decomposes the problem into three subproblems and introduces a heuristic for each of them: (1) Which pieces of code to partition? (2) Which of them to assign to permanently mapped banks? and (3) How to divide the remaining ones among switchable banks? We integrate the algorithm, together with earlier ones, in an open-source compiler and test the resulting solution on synthetic as well as actual commercial IoT software bases, thereby demonstrating its advantages and drawbacks.
    [Show full text]
  • Control Design and Implementation of Hard Disk Drive Servos by Jianbin
    Control Design and Implementation of Hard Disk Drive Servos by Jianbin Nie A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Engineering-Mechanical Engineering in the Graduate Division of the University of California, Berkeley Committee in charge: Professor Roberto Horowitz, Chair Professor Masayoshi Tomizuka Professor David Brillinger Spring 2011 Control Design and Implementation of Hard Disk Drive Servos ⃝c 2011 by Jianbin Nie 1 Abstract Control Design and Implementation of Hard Disk Drive Servos by Jianbin Nie Doctor of Philosophy in Engineering-Mechanical Engineering University of California, Berkeley Professor Roberto Horowitz, Chair In this dissertation, the design of servo control algorithms is investigated to produce high-density and cost-effective hard disk drives (HDDs). In order to sustain the continuing increase of HDD data storage density, dual-stage actuator servo systems using a secondary micro-actuator have been developed to improve the precision of read/write head positioning control by increasing their servo bandwidth. In this dissertation, the modeling and control design of dual-stage track-following servos are considered. Specifically, two track-following control algorithms for dual-stage HDDs are developed. The designed controllers were implemented and evaluated on a disk drive with a PZT-actuated suspension-based dual-stage servo system. Usually, the feedback position error signal (PES) in HDDs is sampled on some spec- ified servo sectors with an equidistant sampling interval, which implies that HDD servo systems with a regular sampling rate can be modeled as linear time-invariant (LTI) systems. However, sampling intervals for HDD servo systems are not always equidistant and, sometimes, an irregular sampling rate due to missing PES sampling data is unavoidable.
    [Show full text]
  • Computer Peripheral Memory System Forecast
    OF NBS H^^LK,!,, STAND S. TECH PUBLICATIONS | COMPUTER SUici^CZ^i TECHNOLOGY: COMPUTER PERIPHERAL MEMORY SYSTEM FORECAST QC 100 U57 NBS Special Publication 500-45 #500-45 U.S. DEPARTMENT OF COMMERCE 1979 National Bureau of Standards NATIONAL BUREAU OF STANDARDS The National Bureau of Standards' was established by an act of Congress March 3, 1901 . The Bureau's overall goal is to strengthen and advance the Nation's science and technology and facilitate their effective application for public benefit. To this end, the Bureau conducts research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety. The Bureau's technical work is performed by the National Measurement Laboratory, the National Engineering Laboratory, and the Institute for Computer Sciences and Technology. THE NATIONAL MEASUREMENT LABORATORY provides the national system of physical and chemical and materials measurement; coordinates the system with measurement systems of other nations and furnishes essential services leading to accurate and uniform physical and chemical measurement throughout the Nation's scientific community, industry, and commerce; conducts materials research leading to improved methods of measurement, standards, and data on the properties of materials needed by industry, commerce, educational institutions, and Government; provides advisory and research services to other Government Agencies; develops, produces, and distributes Standard Reference Materials; and provides calibration services. The Laboratory consists of the following centers: Absolute Physical Quantities^ — Radiation Research — Thermodynamics and Molecular Science — Analytical Chemistry — Materials Science.
    [Show full text]
  • Manufacturing Equipment Technologies for Hard Disk's
    Manufacturing Equipment Technologies for Hard Disk’s Challenge of Physical Limits 222 Manufacturing Equipment Technologies for Hard Disk’s Challenge of Physical Limits Kyoichi Mori OVERVIEW: To meet the world’s growing demands for volume information, Brian Rattray not just with computers but digitalization and video etc. the HDD must Yuichi Matsui, Dr. Eng. continually increase its capacity and meet expectations for reduced power consumption and green IT. Up until now the HDD has undergone many innovative technological developments to achieve higher recording densities. To continue this increase, innovative new technology is again required and is currently being developed at a brisk pace. The key components for areal density improvements, the disk and head, require high levels of performance and reliability from production and inspection equipment for efficient manufacturing and stable quality assurance. To meet this demand, high frequency electronics, servo positioning and optical inspection technology is being developed and equipment provided. Hitachi High-Technologies Corporation is doing its part to meet market needs for increased production and the adoption of next-generation technology by developing the technology and providing disk and head manufacturing/inspection equipment (see Fig. 1). INTRODUCTION higher efficiency storage, namely higher density HDDS (hard disk drives) have long relied on the HDDs will play a major role. computer market for growth but in recent years To increase density, the performance and quality of there has been a shift towards cloud computing and the HDD’s key components, disks (media) and heads consumer electronics etc. along with a rapid expansion have most effect. Therefore further technological of data storage applications (see Fig.
    [Show full text]
  • The Ultimate C64 Overview Michael Steil, 25Th Chaos Communication Congress 2008
    The Ultimate C64 Overview Michael Steil, http://www.pagetable.com/ 25th Chaos Communication Congress 2008 Retrocomputing is cool as never before. People play Look and Feel C64 games in emulators and listen to SID music, but few people know much about the C64 architecture A C64 only needs to be connected to power and a TV and its limitations, and what programming was like set (or monitor) to be fully functional. When turned back then. This paper attempts to give a comprehen- on, it shows a blue-on-blue theme with a startup mes- sive overview of the Commodore 64, including its in- sage and drops into a BASIC interpreter derived from ternals and quirks, making the point that classic Microsoft BASIC. In order to load and save BASIC computer systems aren't all that hard to understand - programs or use third party software, the C64 re- and that programmers today should be more aware of quires mass storage - either a “datasette” cassette the art that programming once used to be. tape drive or a disk drive like the 5.25" Commodore 1541. Commodore History Unless the user really wanted to interact with the BA- SIC interpreter, he would typically only use the BA- Commodore Business Machines was founded in 1962 SIC instructions LOAD, LIST and RUN in order to by Jack Tramiel. The company specialized on elec- access mass storage. LOAD"$",8 followed by LIST tronic calculators, and in 1976, Commodore bought shows the directory of the disk in the drive, and the chip manufacturer MOS Technology and decided LOAD"filename",8 followed by RUN would load and to have Chuck Peddle from MOS evolve their KIM-1 start a program.
    [Show full text]
  • Z80 Bank-Switching Scheme An101
    Z80 BANK-SWITCHING SCHEME AN101 1. INTRODUCTION 1. Scope: This Application Note gives a description of a circuit design allowing the classic Z80 microproces- sor to access expanded memory, beyond the 64K bytes made readily available by its 16 address lines, A0 through A15. 2. Z80 microprocessor: Though it has been over 20 years since the introduction of the Z80, this family of microprocessors still finds application in new designs. This is because the Z80 is still cost-effective for many 8-bit applications; because many users have a large library of tested code for the Z80; and because the parts are readily available from several manufacturers, easing supply concerns that apply to sole-sourced processors. 3. Applicable chips: This Application Note applies to the classic Z80 microprocessor. It can also be applied to the newer Z84C15, which comprises a Z80 CPU, a clock generator, four Z80 CTC channels, two Z80 SIO channels, DMA, chip select signals, and glue logic in a 100-pin quad flat pack. However this external bank-switching circuitry is not necessary for members of the Z80180 family, which have a built-in MMU (memory management unit) on-chip. 2. DESIGN GOALS 1. Program memory: We wanted to expand program memory space to 128K bytes for our application. We needed to support in-circuit reprogramming, so we chose the AMD 29F010 flash memory device. This +5 volt part does not require a +12 volt power supply for programming. After the flash chip is initially programmed at the factory with the bootstrap loader and the current application code, it can later be reprogrammed in the field over the RS-232 serial port.
    [Show full text]
  • Digital Preservation Guide: 3.5-Inch Floppy Disks Caralie Heinrichs And
    DIGITAL PRESERVATION GUIDE: 3.5-Inch Floppy Disks Digital Preservation Guide: 3.5-Inch Floppy Disks Caralie Heinrichs and Emilie Vandal ISI 6354 University of Ottawa Jada Watson Friday, December 13, 2019 DIGITAL PRESERVATION GUIDE 2 Table of Contents Introduction ................................................................................................................................................. 3 History of the Floppy Disk ......................................................................................................................... 3 Where, when, and by whom was it developed? 3 Why was it developed? 4 How Does a 3.5-inch Floppy Disk Work? ................................................................................................. 5 Major parts of a floppy disk 5 Writing data on a floppy disk 7 Preservation and Digitization Challenges ................................................................................................. 8 Physical damage and degradation 8 Hardware and software obsolescence 9 Best Practices ............................................................................................................................................. 10 Storage conditions 10 Description and documentation 10 Creating a disk image 11 Ensuring authenticity: Write blockers 11 Ensuring reliability: Sustainability of the disk image file format 12 Metadata 12 Virus scanning 13 Ensuring integrity: checksums 13 Identifying personal or sensitive information 13 Best practices: Use of hardware and software 14 Hardware
    [Show full text]