MITS ALTAIR computers, docs, resources

This page last updated Oct 21 2013 (c) Herb JOhnson 2013. .

Death of Ed Roberts, MITS Altair developer

Death of Ed Roberts, MITS Altair developer: On April 1 2010, Dr. Ed Roberts, M.D., died of pneumonia, at age 68. He was the founder of MITS in 1969, and the designer of MITS' Altair 8800 computer in 1975 which included the "Altair bus", the 100 pin connectored backplane which became known as the "S-100" bus within a few years. We have a tribute page to him at this link. Meanwhile, my S-100 home page lists over 140 companies which produced S-100 cards or systems; and has links to many pages about S-100 technology and to individual S-100 company products and histories. Their legacy, and the legacy of all the companies and software and hardware subsequently created by those employed by those companies, are also a tribute to Ed Roberts. - Herb Johnson

MITS and Altair history

[Altair 8800] First offered to the public in January 1975 by MITS in a Popular Electronics front-page article, this is an image of an Altair 8800 computer. It was designed by MITS founder and president Ed Roberts in 1974. It initially contained several major components: a 4-slot motherboard with bus connectors of 100 pins each, soon to be called the "S-100 bus"; a CPU card with an Intel 8-bit processor (8080); a memory card initally with 256 BYTES of memory; a front panel of lights and switches; and a power supply. The design of the computer was completely "open"; in fact it was sold as a kit, with full documentation including schematics and operating descriptions. Other cards were to follow, and they did.

Why the "S-100 bus"? And why the name "Altair"? These questions are asked so often I devoted a Web page to their origins. Another common question is: "Was the MITS Altair 8800 the first personal computer?" Nope, but it was important and read Web this page to see why I believe that and to see a 2007 Web site which had a good description of other "first" and "personal" computers.

[Altair inside] Here on the left is an inside view of the Altair, with various cards. The card with the white connector and white wires is the CPU board; behind it are two memory cards; the back is an I/O card. The earliest Altair had just a four-slot motherboard, additional slots were added four at a time. Note that in the read of this Altair is a row of capacitors, part of the earliest Altair power supplies. Every surviving Altair today will likely have different cards, some of NONE of which may be MITS cards.

[Altair memory] To get some idea of this level of technology, compare this MITS *one thousand byte* memory card to the *one Megabyte* SIMM memory pictured here on the left. The earliest MITS memory card was sold with only TWO memory chips, 2101 Intel memory with 256 X 4 bits per chip. This board had six more 2101's added to bring it up to a "full" 1K bytes of memory. Note that the circuit traces and the edge connector on this board are grey; that's "tinned" in the circuit-board trade and this is very distinctive of early MITS Altair cards.

While the Altair was not the very first microprocessor-based "personal" computer or computer kit, the MITS Altair 8800 is often cited as the "first" POPULAR personal computer due to its availability and widespread press coverage; its low cost which allowed thousands to buy it; and its expandability which led to the founding of many companies to offer S-100 bus compatible products. The first compatible company was IMSAI Inc. with their IMSAI 8080. IMSAI named their Altair-compatible bus "the S-100 bus" due to the 100-pin connector. Here is a list of the Altair bus lines. This bus was adopted by over 100 companies large and small over the next several years; the bus became an IEEE standard. An early MITS software product, MITS BASIC, was written by a two-person company called "Micro-soft"; the persons were Bill Gates and Paul Allen. Competitor IMSAI was a very early adopter of Digital Research's CP/M which was the dominant microcomputer operating system of the era.

This history makes a strong case that MITS and the Altair 8800 catalyzed the microcomputer computer revolution of the mid-1970's. However, others reasonably debate that other products and events were also important or critical to the history of personal computing or information technology. History, after all, is a backward-looking opinion about events. In history, it is very rare that one person, one idea, or one product exclusively determined the future, or was created in a vacuum. This site is primarily devoted to S-100 history; there is no debate as to the first S-100 computer.

Other sites have more history about Ed Roberts, MITS and the Altair product line; so my notes on MITS history are brief. MITS made a number of electronic instruments before offering the Altair. MITS, and another computer product company called ICOM, were bought by disk drive manufacturer Pertec, Inc. in mid-1977. Former MITS products became part of Pertec's "PCC MicroSystems Division", so some MITS items may be branded "Pertec" or "ICOM". Percom accumulated a number of computer product companies over time. According to one former Pertec employee Tom Sanderson, Pertec designed some additional computer products and systems which were only software-compatible with the Altair; as well as other computer products. Others say MITS-based product production ceased in mid-1978. All those products were later dropped by Pertec.

What is the status of Pertec today? Pertec was bought but maintained as a subsidiary by a number of companies: by German company Trimuph-Adler around 1979; in April 1986 Volkswagen, who at various points funded Pertec, kept PCC after selling Trimuph-Adler to Olivetti. In any event, other references suggest that Pertec Computer Corporation persisted as a corporation through at least 1982. There is a 1989 and a 1990 reference to a "DDC Pertec" in Chatsworth CA, as a manufacturer of tape and disk drives. In 2006 EPA reports a commercial facility exists at the same Chatsworth address, but I can't find any activity about DDC Pertec on the Web after the 1980's. I do not believe that a 2006 French company named Pertec is related, their site has no history information.

Altair 8800 replicas and originals

There is often talk about building replicas of the MITS Altair 8800. Until recently it's been mostly talk. With the rise of the Internet in the 90's and 21st century, original Altairs are still available. (Incidently, most people only know of "the Altair" or "the 8800" as the 8800a model, although there was a "b" and a "turnkey" model; and a 6800-based MITS 680 that sold poorly.)

In year 2011, one can buy an original MITS Altair 8800a or other models from on-line auction sites. Parts like boards sell for tens or a few hundred dollars or two; systems in various condition sell for on the order of a thousand or two thousand dollars. I do not endorse any Web auction sites in particular. There may also be private sales or dealer sales via the Web.

As of 2007, there are two Altair 8800 hardware emulators in active development with working prototypes - I've seen both, I've touched 'em, they are real. As of Feb 2007, neither is available for general sale. As of 2007, there is also a "faux Altair" 8800, available as a kit in small-run production. Check with the sites listed below for details.

Rich Cini of Altair32.com has worked on and offered a software emulator for the Altair for a number of years, previously developed by Glaus Giloi. Apparently in 2004 or so, Rich decided to work on a hardware front-panel replica with 8080 emulation. By 2006 he had a working prototype. It's a stand-alone front panel cosmetically identical to the 8800a front panel. An 8051 microcontroller and other hardware make it a USB 2.0 slave device which Rich supports on his altair32 emulator under Windows. That emulator also runs two RS-232 ports on the front panel. Other connection options are described on the Web site. As of November 2006, Rich is working to complete another design run of this product; units were not available for sale at that time. No updates to the project's status as of Feb 2007.

Vince Briel of Briel Computers is developing a product called AltairPC. This device is an 8800a front panel replica attached to a PC ATX-class case and power supply. The case can hold a Pentium 4 motherboard to run an emulator. The front panel replica hardware runs 8080 code in 256 BYTES of memory as emulated by a AVR microcontroller. The replica has a USB connector which is connected to the PC/Windows system. The replica's AVR processor can be reprogrammed via an in-circuit programmer to the AVR device. You can also toggle in 8080 programs and run them directly on the front panel. As of Sept 2006 the Web page says "no emulator has been modified to work with the front panel" and asks for help. As of Feb 2007, the AltairPC is not yet available according to the Web site. An associated discussion forum is only about the Apple I replica sold by Briel.

Late in 2006, Grant Stockly announced he would make available several kits which are duplicates of the original MITS Altair 8800. Some kits were sold on eBay; the first was delivered Dec 7th 2006 to Howard Harte. As of Feb 2007, at least several kits were sold. This kit included boards, case, front panel, 4-slot motherboard; the switching power supply is an improvement from the original. Many MITS items were duplicated down to original board layouts and logos; they are for the most part different only in PC board material or apparent age, or minor cosmetic features like chips with post-70's date codes. It is a significant achievement that he successfully replicated an early Altair 8800. Stockly himself says one of his goals is to give others the "Altair experience" of building the kit from that era. He reported one system ran for over 50 days continuously, before he turned it off. For more information, check his Stockly.com discussion Web site; or his Altair Kit Web site. A Web search may find other owners of these kits. A photo of one of these was in an early 2007 issue of "Make" magazine.

I talk a little more about "replicas" on this linked WEb page.

MITS and Altair resources

I have a seperate Web page of S-100 related Web pointers. There are many Web sites dedicated to the Altair 8800, or to MITS; and sites which include the 8800 among many other old computers.

IN 2011 I had some email exchanges with Martin Eberhard about his restoration of a 6800-based MITS 680. It's an interesting little system. Not S-100 but it used the same bus connectors!

In the fall of 2011, I corresponded with Martin Eberhard, another 6800 system owner. He has a number of MITS "Altair 680" systems. MITS is less-well known for their Altair 680, an non-S-100 based 6800 computer. I created a Web page from Martin's correspondence about his work on restoring his Altair 680 system and some software he wrote to support it. [I do not have a MITS 680 system.]

Former Pertec employee Tom Sanderson has a nice MITS and Altair Web site called "Virtual Altair" about the various product lines associated with MITS, Pertec and Icom. He's actively working on restoring hardware of the period.

For a list of available Altair docs look below.
Here is a list of the IMSAI and Altair bus lines.
For a list of all S-100 docs click there.
Again, here is how to order S-100 stuff and email @ me.

SOme of the earliest floppy disk controllers were adapted to the MITS Altair 8800. read this Web page about the first floppy controllers for CP/M.

Altair technical information

In Sept and Oct 2006 W. Tom Sanderson of the "virtual Altair" Web site and program contacted me about his work in progress on his MITS/Altair and Pertec early equipment. Here's some of his comments, with permission. "PCC" below refers to Pertec Computer Company, which bought iCOM and MITS as described in the history above. - Herb Johnson

Pertec floppy drives

Tom says the Pertec drives come with black or white bezels (interchangable) and DC or AC motors. There are two door types, one with aluminum doors and another with white plastic doors. MITS drives for hard-sectored use had holes near the CENTER for the sector and index holes, not holes near the EDGE like the very oldest 8-inch drives.There are versions of drives with a 50-pin interface and others with a Pertec interface. To identify drives by model and revision, Tom offered me the following "key to understanding the Pertec drive numbering system".

"The first digit identifies drive motor type. A FD4xx number indicates a DC motor and a 5xx number indicates an AC Motor.

The second digit identifies density. A FDx0x drive is single density and a FDx1x drive is single or double density. MITS used both FD410 and FD510 drives, even though the MITS controller was only single density.

The third digit is interface type. A FDxx0 is the "Basic" PRE-STANDARD Pertec interface an it is not 50 pins. A FDxx1 indicates a Basic interface with "Internal Daisy Chain". A FDxx4 number indicates a standard Shugart Interface. These drives were not used by MITS. Pertec used them in the PCC2000. They may be in the iCOM 3812,I'm not sure.

An extension to the FDxxx number specifies Model Revision, for example FD514-06."

Tom describes what he knows about the production history of use of these drives. "The original Altair drive was an FD400. Later production used a FD-510. I've also seen a FD-511 drive used with a FD-510 FD board. There are six versions of the FD-514. Changing versions required few component changes in addition to jumper changes. The FD514-06 revision provides a standard Shugart configuration. Another revision supported hard sector operation."

MITS floppy controllers

Tom described the MITS floppy controllers: "I've identified three variation of [MITS] 8-inch controllers. The most obvious difference is the internal cable used to connect the two-board controller to the drives. The 5.25-inch controller looks like the 8-inch controller [board] pair. The controller is modified for 16-hard sector use. The drives were Shugart, so that is a good sign that that there is hope [I can] substitute [Shugart 800/801] 8-inch drives.

Tom later provided a list of MITS floppy controller revisions as follows:

BD1 Rev 0 X2 - This one has the white bus strips
BD1 Rev 0 X3 - This one has the white bus strips
BD1 Rev 0 X4 - 1976 Version
BD1 Rev 0 X4 200228 Rev F. - 1976
BD1 1977 200290 1A
Disk #2 Rev 0 X2 - My board is a tan color, not green
Disk #2 Rev 1
Disk #2 200192-1 - Ansley flat ribbon connector

Tom says "MITS did not make and double-density controllers for the Altair. iCOM made a double-density dual-drive cabinet that contained it's own controller. The iCOM 3712(SSSD) and 3812 (SSDD) dual-drive cabinets contained a controller and the S-100 board was just an interface board."

DCDD notes: 3200/250284A notes

In November 2006 I received two sets of schematics for the MITS "disk board #1" and "disk board #2". One set was part of the MITS 3200 document 250284A dated April 1978 on the two-board disk controller. Another set was copied from a less-well-drafted set of schematics, unlabeled and undated; the provider said they were from a "March 1976 88-DCDD preliminary manual". In addition, I have a set of schematics from the manual "Altair 88-DCDD Floppy Disk Documentation" for July 1977, which covers use with the FD-400 Pertec drive and describes "board 1" rev 0-X2 and rev 0-X4 and "board 2" rev 0-X2 and rev 1.

The three sets of schematics, which I'll call "250284A" and "Mar 76" and "Jul 77" respectively, are ROUGHLY the same, with the same circuits, chips, and designations. But a close comparison by me (Herb Johnson) revealed the differences detailed below. These are changes in components for timing circuits and added R/C components for signal delays.

The "Mar 76" schematics lack some R/C circuits added between some chips in the 250284A document. Typically the circuit is a series resistance of 470 ohms, followed by a 470 picofarad capacitor to ground; this is called a "low pass filter" and it introduces a short delay to changing logic states. IC connections where this circuit is added in the 250284A document include the following on disk board #1, sheet #1: E3 pin 13 to E5 pin 1; F3 pin 13 to E2 pin 12 (13). On sheet #2, it's between F2 pin 13 to G2 pin 1. This is not a complete list. The "Jul 77" schematics ALSO have these R/C circuits as described on the 250284A schematics, and the same component values. They are noted on the "Jul 77" schematics as "on REV 1 board only". This is not a complete list of differences.

In addition, there are different resistor values for the R/C circuits associated with the "one-shots" (monostable multivibrator chips which produce pulses of specific timing) between the two sets of schematics. The following are on disk board #1, sheet #1:, for the 250284A document R3=4.3K, R4=8.45K, R11=4.3K R12=12.1K R6=8.45K. For the "Mar 76" document R3=10K, R4=20K, R11=??? R12=20K R6=20K. For the "Jul 77" schematics: R3=10K, R4=20K, R11=10K, R12=22K R6=20K. Finally, some of the one-shot resistors on the 250284A ONLY are variable, probably trimpots. Disk board #2 sheet 2 has variable resistors on A7 pin 1, B1 pin 15, B2 pin 7 among others. This is not a complete list of differences.


MITS Altair S-100 Documentation List

Altair (MITS) and related documentation available (copies) are describe below. PAY CLOSE ATTENTION to the descriptions below when ordering. Please include these descriptions when ordering. We will accept orders for complete manuals or for the SPECIFIC sections named with page counts. Price is based on page count so BE SPECIFIC WHEN ORDERING, USE THESE EXACT DESCRIPTIONS.

Original 1975 Altair 8800 documents:
     Altair 8800: front panel address and data switches on solid grey
                  background
     Altair 8800a: as above, some changes in f.p. and logos

     1) Altair 8800 Assembly manual, 103 pgs
        For assembly of front panel, CPU, chassis, power supply, bus.
        assembly hints, sketches of cards & chassis, sketches of parts
        and their insertion, wiring directions, parts lists. No schematics.
     2) Altair 8800 Operators manual, 100 pgs
        Tutorial. Describes binary arithmetic, organization of 8800 system,
        programming of 8080 processor, front panel operation and display,
        descriptive list of 8080 instructions. No electronics references.
     3) Altair 8800 "Theory of Operation, Manual & Schematics" 24 pgs
        Covers CPU, 1K RAM, power, display/control panel.
        Descriptions of circuit operation. Bus definition.
        Schematics. Checkout procedure.

Altair 8800b documents: 1976, reprinted June 1977
     8800b: front panel address and data switches on dark background
            with white horizontal strips

     1) Altair 8800b Documentation, 280 pgs TOTAL except Ch 5.
        front panel with address and data switches version,
             bus, power, interface board, & CPU schematics
        operation of front panel. Troubleshooting. Parts list.
        Intel 8080 Users Manual and Intel chip data sheets.
	  This manual is divided as follows:
        Ch. 1 - introduction and content lists. 12 pgs
        Ch. 2 - Operators Guide 15 pgs
            "Intel 8080 Microcomputer System User's manual" - 60 pgs
        Ch. 3 - Theory of Operation 28 pgs
            Intel chip data sheets: 30 pgs
            Schematics & bus definition: 30 pgs
        Ch. 4 Troubleshooting: 68 pgs 
        Does not include chapter 5 on assembly of system or cards.
        Appendix A - parts lists: 9 pgs
     2) Altair 8800b chapter 5: Assembly - 75 pgs.
        Assembly instructions for 8800b system.
        Was not distributed by MITS with assembled 8800b systems.

Altair 8800b-t: July 1977
     TURNKEY system, run/stop and reset switches ONLY, BLACK background.

     1) Altair 8800b-t Turnkey Computer Documentation, 83 pgs TOTAL
        Front panel with run/stop/halt switches version, Turnkey module.
        Schematics and description for turnkey control card and front panel.
        Does not include chapters "Intel 8080 users manual" below.
        Does not include chapter 5 on assembly of Turnkey system or cards.
        Includes the following chapters:
        Ch 1: Introduction and contents lists: 6 pgs
        Ch 2: Theory of Operation, Schematics: 24 pgs
        Ch 3: Advanced Operation: 20 pgs
           serial port and power operations
        Ch 4: Troubleshooting and index: 8 pgs
        Does not include Chapter 5 on assembly of system or cards.
        Appendixes: 20 pgs
           parts lists, 230V operation, bus description
     2) Altair 8800b-t Turnkey chapter 5: Assembly., 110 pages.
        (Confirm we have this available.) How to assemble the 8800b-t.
        Was not distributed by MITS with some assembled 8800b-t systems.
     3) Intel 8080 microcomputer system users manual, 84 pages
        As distributed with "8800b Turnkey Computer" docs.
           Duplicates information in chapter2 of 8800b manual above.
        Copy of Intel's 8080 hardware and instruction set description,
        hardware chip descriptions for 8080, 8212, 8216, 8224.

     4) "MITS 300 Computer System - 
        Theory of Operation and Maintenance Manual - Turnkey Module"
           doc #200786A June 1978
           Chapter 4 ONLY on Theory of Operation, pgs 4-9 to
           4-28, 20 pgs, no schematic, for Turnkey board for 8800b-T
           system, plus schematic and description for run/stop front panel.

     5) Turnkey Module modifications, various notes from MITS:
     The 88-SYS-CLG modification brings the 8800b/8800bt to a full 64K
         by making the the PROMS "phantom" on the Turnkey Module
     * Tech Notes on 88-SYS for 8800B-T Oct 79, 8 pgs
     * Tech notes as above, different version, 7 pgs
         affects boards 200360, 200375, 200359

Altair 8800b-sm, 8800b-dm: TURNKEY system, run/stop & reset switches, floppy drive
     1) Altair 8800b-sm & -dm Computer Documentation, 100 pgs
        Front panel with run/stop/halt switches version, Turnkey module.
        Schematics and description for turnkey control card and front panel.
        Does not include chapters "Intel 8080 users manual" below.

     2) Intel 8080 microcomputer system users manual, 84 pages
        As distributed with "8800b Turnkey Computer" docs.
           Duplicates information in chapter 2, 8800b above.
        Copy of Intel's 8080 hardware and instruction set description,
        hardware chip descriptions for 8080, 8212, 8216, 8224.

Altair disk systems and controllers manuals:

    Note: be advised that anyone purchasing the 88-DCDD manual or the 3202 manual
    may need the NWD mod doc and may wish to have all available
    versions of the controller schematics. A former Pertec employee said 
    "I think it is likely that most old controllers were modified for "NWD" timing".

    MITS Timsharing BASIC Version 2 Reference Manual (copy)
        Feb 1979, 60 pages
        diskette based multiuser BASIC, using 3202 controller/drive system

    Altair Disk Operating System Documentation (copy)
        June 1977, 127 pages
        Chapters on monitor, text editor, assembler, linker, debug
        NOT CP/M! 

    MITS Memory Diagnostics, doc #103239, 4 pgs
        Says pgm is "&MTST" on a MITS "DOS disk"
        I have a disk copy, but the diskette is 32-hard-sectored. 
        I'm told the disk can be read in the MITS 88-DCDD single-drive cabinet 
        or the Pertec 3202. The "(NWDD)" on the label indicates the New Write Delay was
        used to write the diskette. The "Pertec Application Note - Hard Sectored"
        provides background on Pertec's view of hard-sectored formatting. 

    Altair 88-DCDD Floppy Disk Documentation (copy)
        July 1977, 318 pages total
        Pertec FD-400 drive, two board floppy controller, disk buffer board
        "board 1" rev 0-X2 and rev 0-X4
        "board 2" rev 0-X2 and rev 1
        assembly, tests, schematics, parts lists
        hand notes for 8-inch drive timing of one-shots (74121's)
        includes "Pertec FD400 Disk Drive Installation Notes", Mar 1977, 18 pgs

    "Pertec Application Notes - Hard Sectored
         Formatting for FD400 Flexible disk drives". 1976, 17 pages
 
     Pertec / PCC "FD400 FD500 Flexible Disk Drives"
         manual 600500, 1978. 90 pages
         for drives 600281 (FD4X0, FD5X0) , 600261 (FD51X)
         Schematics offered seperately as below

     "Pertec FD Control B" schematics, document 600260
         for board 600261. 7 sheets 11X17, 1977

     "Pertec FD Control D" schematics, document 600280
          for board 600281. 6 sheets 11X17, 1977

    "Pertec FD BASIC II DC" schematics, document 600320
          for board 600321. 7 sheets 11X17, 1975-76

    "Pertec FD BASIC II A" schematics, document 600265
          for board 600266. 8 sheets 11X17, 1976

    "Pertec FD BASIC II AC" schematics, document 600250
         for board 600251. 6 sheets 11X17

    Altair 88-MDS Minidisk Documentation Preliminary
        July 1977 w/ updates April 1978, 100 pages plus notes
        88-MDS two-board system and 88-MDDR 5.25 inch drive
        schematics, PROM listings, some code, more
        6 pgs of hand-written "tech notes" poorly reproduced
        hardware is apparently similar but not identical to 88-DCDD

   Various notes, FD400 and 88-DCDD cards, for NWD - New Write Delay - modification
   * "Disk Hardware Notes" by Tom Dursten, 88-disk control mods, FD400, 2 pgs
   * Altair Disk test programs, Apr 1976, 5 pgs w/ assembly source
   * "Disk Hardware Notes" by Tom Dursten, timing on FD400 controller one shots, 2 pgs
   * Disk Control board DB-37 to 20+20+10 pin connectors, cable construction, 7 pgs

   "Altair Hard Disk 88-HDSK Preliminary Documentation", Oct 1977
       138 pgs plus 4 sheets 11X17 schematics
       *new* 35 page addendum, with 8X300 code (PDF available)
       MITS interface to Pertec D3422 drive, 5MB fixed 5MB removable
       Docs cover processor card with 8X300 processor which cables to the
       MITS (S-100) 88-4PIO parallel card; and data card; and interface card to
       Pertec drive. The three cards are boxed separately from the
       Pertec drive and the Altair system.

    "MITS 3200 Users Manual - Disk Controller Boards"
       doc 250284A, April 1978. 82 pgs manual, 18 pgs 11X17 schematics and cabling
       Theory of Operation for boards #1 and #2, 
       "MITS 3200" Disk Board #1 and #2 schematics, appendices. document 250284A
       
       also available; 6 pgs 11X17 for Disk Board #1 and #2 schematics
       from a March 1976 88-DCDD "preliminary" manual. They are an
       earlier version, does not have R/C delay circuits or trimpots
       as added to 3200/250284A above  see "3200/250284A notes" for discussion

Other Altair hardware documents:

     Altair 8800 88 2-SIO docs, 50 pgs
        Theory of operation, schematics, assembly, parts list, serial
        connectors and signals.
     Altair 88-PMC PROM memory card, 30 pgs
        1702 PROMs. Theory of operation, schematics, assembly.
     Altair 88-4MCD "4K RAM Board", 26 pgs
        Sept 1975. TMS 4030 or C 2107A 4K by 1 RAM chips, along top of card.
        Circuit description, schematic, assembly and test instr., errata.
     Altair 88-S4K Synch 4K RAM docs, 60 pgs
        Feb 1977. TMS 4060 4K by 1 RAM chips, along right of card.
        Logic descriptions, schematics, assembly, test, signal waveforms.
     Altair 88-16K static RAM card, (88-16 MCS) 26 pgs
        1977. THeory of operation, timing, layouts, schematics, assembly.
     Altair 88-VI/RTC vector interrupt, real-time clock, 36 pgs
        1976. THeory of operation, schematics, assembly, errata
     Altair 88-16MCD dynamic memory card, 55pgs
        July 1977. MK4096 4K by 1 chips.
        THeory of operation, schematics, assembly, troubleshooting.
     Altair 88-4 Parallel I/O card (4PIO), 28 pgs
        1975. Four port parallel card: operation, assembly, schematics.
     Altair 88-ACR audio cassette interface, 53 pgs. (2 cards)
        June 1975. SIO-B serial card & ACR modem board.
     MITS 3200 series Floppy Disk System *preliminary*, 18 pgs
        MITS 3202 schematics and cabling sketches only
     Altair 88-NO power controller, 31 pages
        8 relay AC control card: theory, schematics, assembly, test.
     Altair 4K Dynamic RAM Assembly manual, 24 pgs
     Percom CI812 Cassette/Terminal I/O, schematics only, 10 pgs

Altair software and miscelaneous

     Altair BASIC reference manual, w/Extended BASIC, Dec 1975, 104 pgs
     Mits Programming System I, rev 2.2, 27 pgs (line printer)
     Altair Programming System II rev 3.0, 58 pgs
			assembler, debugger
     Altair Software Library update, 60 pgs
        short descriptions of several dozen programs, coding sheet,
        source listings of: JAMON, kill the bit, target.
        JAMON is five pages of code listings. Commands are to load
        and dump and "go", all in octal (bleah). Kill the bit is a
        one-page listing of a game using the front panel only.
        Target is a 9-page listing using a VDM video display and
        "bit 7 of an input device" (front panel?).

     Altair 4/1/76, 7/1/76, 8/1/77 retail price lists, 20 pgs

     MIcrosoft BASIC Reference Manual, Jan 1977, 128 pgs
        for BASIC CP/M version 4.41 as MBASIC.COM
        includes an April 1977 addenda, appendix B on CP/M BASIC
        similar to Microsoft BASIC reference manual for MITS, Jan and July 1977

     "MITS Altair Production Test Procedures - Altair 8800B Systems
      Altair 680b Systems". 24 pages. Production test procedures for
      8800a, 8800b, & 680B chassis, and individual MITS board products. 
      16K MCS may be latest product covered; no date on document.

MITS newsletter/magazine "Computer Notes":

(note: 11 X 15 editions will be copied to reduced size 8 X 11:
if you want 11 X 17 copies I must charge for TWICE as many pages.)

     Vol 1 Issue 10, March 1976, 11" X 15" - 12 pgs
     Vol 1 Issue 12, May 1976, 11" X 15" - 16 pgs
     Vol 2 Issue 1, June 1976, 11" X 15" - 20 pgs
     Vol 2 Issue 2, July 1976, 11" X 15" - 24 pgs
     Vol 2 Issue 3, Aug 1976, 11" X 15" - 24 pgs
     Vol 2 Issue 4, Sept 1976, 11" X 15" - 16 pgs
     Vol 2 Issue 5, Oct 1976, 11" X 15" - 12 pgs
     Vol 2 Issue 6, Nov 1976, 11" X 15" - 32 pgs
     Vol 2 Issue 7, Dec 1976, 11" X 15" - 16 pgs
     Vol 2 Issue 8, Jan-Feb 1977, 8" X 11" - 28 pgs
     Vol 2 Issue 9, March 1977, 8 X 11, 24 pages (from copy)
     Vol 2 Issue 10, Apr 1977, 8" X 11" - 28 pgs
     Vol 2 Issue 11, May 1977, 8" X 11" - 28 pgs
     Vol 3 Issue 1, June 1977, 8" X 11" - 28 pgs
     Vol 3 Issue 2, July 1977, 8" X 11" - 20 pgs
     Vol 3 Issue 3, Aug 1977, 8" X 11" - 20 pgs
     Vol 3 Issue 4, Sep 1977, 8" X 11" - 28 pgs
     Vol 3 Issue 5, Oct 1977, 8" X 11" - 36 pgs
     Vol 3 Issue 6, Nov 1977, 8" X 11" - 36 pgs
     Vol 3 Issue 7, Jan-Feb 1978, 8" X 11" - 36 pgs



Herb Johnson
New Jersey, USA
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