Remembering COMPAQ
This commit is contained in:
Jeff Parsons
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---
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layout: post
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title: Compaq DeskPro 386
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title: COMPAQ DeskPro 386
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date: 2015-02-22 11:00:00
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category: 80386
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permalink: /blog/2015/02/22/
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@ -11,15 +11,15 @@ machines:
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uncompiled: true
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---
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I finally dumped the [Compaq DeskPro 386/16 ROMs](/devices/pc/bios/compaq/deskpro386/) from the motherboard I bought
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I finally dumped the [COMPAQ DeskPro 386/16 ROMs](/devices/pc/bios/compaq/deskpro386/) from the motherboard I bought
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on ebay last year, so I'm ready to begin adding 80386 support to PCjs.
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I'd also like to locate a copy of the "Compaq DeskPro 386 Technical Reference Guide, Volumes 1 and 2". It's not hard
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to find Compaq Maintenance and Service guides online, but their Technical Reference guides are much rarer, perhaps because
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I'd also like to locate a copy of the "COMPAQ DeskPro 386 Technical Reference Guide, Volumes 1 and 2". It's not hard
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to find COMPAQ Maintenance and Service guides online, but their Technical Reference guides are much rarer, perhaps because
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they were expensive ($149) and not many were sold. Anyway, I'm hoping to either borrow or buy a copy, and then scan and
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post it.
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A [Compaq DeskPro 386](/devices/pc/machine/compaq/deskpro386/ega/2048kb/) test configuration is displayed below.
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A [COMPAQ DeskPro 386](/devices/pc/machine/compaq/deskpro386/ega/2048kb/) test configuration is displayed below.
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The configuration doesn't run, and the debugger can't disassemble 80386-specific code yet, but this is what I will be
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using to test and debug my changes over the next few months.
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@ -1,6 +1,6 @@
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---
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layout: post
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title: Compaq DeskPro 386 Update
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title: COMPAQ DeskPro 386 Update
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date: 2015-04-16 11:00:00
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category: 80386
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permalink: /blog/2015/04/16/
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@ -11,7 +11,7 @@ machines:
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uncompiled: true
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---
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PCjs can now boot the [Compaq DeskPro 386/16 ROM BIOS](/devices/pc/bios/compaq/deskpro386/).
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PCjs can now boot the [COMPAQ DeskPro 386/16 ROM BIOS](/devices/pc/bios/compaq/deskpro386/).
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There's still a problem with the hard disk controller, which I haven't looked into yet,
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but booting from a floppy works.
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@ -43,7 +43,7 @@ of the 80386's 4Gb address space are physically mapped to this ROM image.
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replacing the ROM in the first megabyte with write-protected RAM; the top 64Kb of that
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RAM must first be initialized with the 64Kb at %000F0000 prior to remapping. It's also
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possible to copy external ROMs from %000C0000 through %000EFFFF into the bottom 64Kb of
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that RAM, but this is only done for ROMs known to contain relocatable code; eg, a Compaq
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that RAM, but this is only done for ROMs known to contain relocatable code; eg, a COMPAQ
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Video Graphics Controller (VGC) Board.
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> Every DeskPro 386 system must have a MINIMUM of 1Mb of RAM, of which either 256Kb,
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@ -53,7 +53,7 @@ to the top of the 16th megabyte (ending at address %00FFFFFF), the last 128Kb of
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is used by the "RAM Relocation" feature. The remaining memory immediately below that
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128Kb (ie, below %00FE0000) can only be accessed by special system software, such as CEMM.
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> Compaq refers to that remaining memory as "Compaq Built-in Memory".
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> COMPAQ refers to that remaining memory as "Compaq Built-in Memory".
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So there you have it. Once the ROM has relocated itself to RAM at the top of the 16th
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megabyte, there are no less than THREE physical address ranges where ROM code and data
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@ -75,7 +75,7 @@ accessible; the other two are not.
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April 19, 2015 Update
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---
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Thanks to some sleuthing by [Michal Necasek](http://os2museum.com/), it turns out that my
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assumptions about A20 management on the Compaq DeskPro 386 were incorrect.
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assumptions about A20 management on the COMPAQ DeskPro 386 were incorrect.
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He noted that, on page 398 of "DOS Internals" by Geoff Chappell, (c) 1994, the author says:
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@ -114,7 +114,7 @@ protected-mode with A20 disabled -- an unwise thing to do on most machines:
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;
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; When we arrive here, the A20 line has been disabled; on most systems, that would
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; mean that the ROM's GDT would only be accessible at the "low" ROM address (%0F0730),
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; not the "high" address (%FF0730). But fortunately, A20 management on Compaq
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; not the "high" address (%FF0730). But fortunately, A20 management on COMPAQ
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; DeskPros affects wrap-around only from the 1st to the 2nd megabyte; no other address
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; range is affected.
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;
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@ -140,12 +140,12 @@ I'm in the process of replacing that work-around with a much more compatible cha
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on 32-bit bus configurations, which involves changing the physical address map for the 2nd megabyte
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to match that of the 1st megabyte whenever A20 is disabled. I could probably get away with remapping
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only the first 64Kb of the 2nd megabyte, but until I'm actually able to run some tests on a real
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DeskPro 386, I'm going to assume Compaq's A20 implementation affected the entire 2nd megabyte.
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DeskPro 386, I'm going to assume COMPAQ's A20 implementation affected the entire 2nd megabyte.
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Here's my Compaq DeskPro 386/16 PCjs test configuration. Set a breakpoint at F000:F498 ("bp f000:f498")
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in the Debugger panel to see the above code in action. When the machine is operating in real-mode, you
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can use the "rp" command to dump all the registers, including the current base and limit values loaded into
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the segment registers.
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Here's my [COMPAQ DeskPro 386/16](/devices/pc/machine/compaq/deskpro386/ega/2048kb/) test configuration.
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Set a breakpoint at F000:F498 ("bp f000:f498") in the Debugger panel to see the above code in action.
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When the machine is operating in real-mode, you can use the "rp" command to dump all the registers,
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including the current base and limit values loaded into the segment registers.
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{% include machine.html id="deskpro386" %}
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@ -1,182 +0,0 @@
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---
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layout: post
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title: "COMPAQ Revisited"
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date: 2016-02-24 14:00:00
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permalink: /blog/2016/02/24/
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---
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I finally obtained a [ROM Dump](/devices/pc/rom/compaq/bios/portable/) from COMPAQ's first machine,
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the [COMPAQ Portable](#compaq-portable).
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At the same time, I thought it would be a good idea to create my own roughly chronological list of COMPAQ machines from
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the 1980s, since they are all machines I would like to see PCjs eventually support:
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+ [COMPAQ Portable](#compaq-portable)
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+ [COMPAQ [Portable] Plus](#compaq-portable-plus-aka-compaq-plus)
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+ [COMPAQ DeskPro](#compaq-deskpro)
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+ [COMPAQ DeskPro 286](#compaq-deskpro-286)
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+ [COMPAQ Portable 286](#compaq-portable-286)
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+ [COMPAQ Portable II](#compaq-portable-ii)
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+ [COMPAQ DeskPro 386](#compaq-deskpro-386)
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+ [COMPAQ Portable III](#compaq-portable-iii)
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+ [COMPAQ Portable 386](#compaq-portable-386)
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+ [COMPAQ 386/20e](#compaq-38620e)
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+ [COMPAQ SLT Series](#compaq-slt-series)
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+ COMPAQ SLT/286
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+ [COMPAQ LTE Series](#compaq-lte-series)
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+ COMPAQ LTE 286
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+ COMPAQ LTE 386
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It's hard to stop at this point, because COMPAQ did produce other 80386-based systems, like those in the "LTE Lite"
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series. But I think I need to stick my original plan and draw a line at the end of the 1980s.
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Below is a random assortment of information I've gathered about some of the above models, with gaping holes for others.
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Currently, the *most* gaping is the [COMPAQ DeskPro 386](#compaq-deskpro-386), because that's the one COMPAQ machine
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that PCjs *already* supports. I just need more time to organize and fill in the details.
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---
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COMPAQ Portable
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---
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PCjs now has a [ROM Dump](/devices/pc/rom/compaq/bios/portable/).
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Reviewed in Byte Magazine, Jan 1983. Reprinted [here](http://blog.modernmechanix.com/byte-reviews-the-compaq-first-pc-clone/).
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Also see [Wikipedia](https://en.wikipedia.org/wiki/Compaq_Portable).
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COMPAQ Portable Plus (aka COMPAQ Plus)
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---
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Reviewed in Byte Magazine, Jul 1984, pp. 247-251: "The Compaq Plus".
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COMPAQ DeskPro
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---
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Introduced June 28, 1984. Reviewed in Byte Magazine, May 1985, pp. 260-267. For use with MS-DOS 2.11.
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**Model** | **Price** | **CPU** | **Options**
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:-------- | :-------- | :---------------- | :------------------------------------------
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Model 1 | $2495 | 4.77-7.14Mhz 8086 | 128Kb RAM, 1 FDD
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Model 2 | $2995 | 4.77-7.14Mhz 8086 | 256Kb RAM, 2 FDD
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Model 3 | $4995 | 4.77-7.14Mhz 8086 | 256Kb RAM, 1 FDD, 10Mb HDD
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Model 4 | $7195 | 4.77-7.14Mhz 8086 | 640Kb RAM, 1 FDD, 10Mb HDD, 10Mb Tape Drive
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COMPAQ DeskPro 286
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---
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Released in 1985 at the same time as the [COMPAQ Portable 286](#compaq-portable-286).
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Reviewed in [InfoWorld](https://books.google.com/books?id=2i4EAAAAMBAJ&lpg=PA15&dq=infoworld%20compaq%20deskpro%201985&pg=PA15#v=onepage&q&f=false),
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May 20, 1985: "Compaq Edges Past AT Speed and Memory: New Products Use Intel 80286 Processor For 30 Percent Speed Boost".
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Updated to 12Mhz in 1987.
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From [InfoWorld](https://books.google.com/books?id=yzAEAAAAMBAJ&lpg=PA56&ots=jBzxR3wcps&dq=%22compaq%20deskpro%20286%22&pg=PA56#v=onepage&q&f=false),
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June 1987: "Compaq Brings 12-Mhz Machine to 286 Market"
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COMPAQ Portable 286
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---
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Introduced in 1985.
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**Model** | **Price** | **CPU** | **Options**
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:-------- | :-------- | :---------------- | :----------------------------------------------------
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| | 8Mhz 80286 | Up to 2.6Mb RAM, 1.2Mb FDD, 20Mb HDD, 10Mb Tape Drive
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See this [COMPAQ Advertisement](http://www.computerhistory.org/revolution/mobile-computing/18/343/1658).
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On July 8, 1985, the [Los Angeles Times](http://articles.latimes.com/1985-07-08/business/fi-9857_1_hard-disk-drive)
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reported:
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>It's not cheap and it's not for everyone. Equipped as described, the portable lists for $10,378 and contains
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about $3,000 worth of extra RAM memory that cannot be utilized by any application software programs now on the market.
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(It can be used to simulate a disk drive to speed up programs, however.)
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>A standard Compaq Deskpro 286 with 512 kilobytes of RAM memory, a 30-megabyte hard disk and a monitor is priced
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at $6,254, compared to IBM's similarly equipped enhanced PC AT that offers only a 20-megabyte hard disk. The Portable
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286 with 512K of memory and 20-megabyte hard disk lists for $6,299.
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COMPAQ Portable II
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---
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The COMPAQ Portable II ("slimmed-down version of the Portable 286", as described in Byte Magazine, Oct 1986) was
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released on February 20, 1986. For use with MS-DOS 3.10.
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**Model** | **Price** | **CPU** | **Options**
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:-------- | :-------- | :---------------- | :------------------------------------------
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Model 1 | $3499 | 6-8Mhz 80286 | 256Kb RAM, 1 FDD
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Model 2 | $3599 | 6-8Mhz 80286 | 256Kb RAM, 2 FDD
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Model 3 | $4799 | 6-8Mhz 80286 | 640Kb RAM, 1 FDD, 10Mb HDD
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Model 4 | $4999 | 6-8Mhz 80286 | 640Kb RAM, 1 FDD, 20Mb HDD
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Also see [Wikipedia](https://en.wikipedia.org/wiki/Compaq_Portable_II).
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COMPAQ DeskPro 386
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---
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Released in late 1986.
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PCjs has detailed information about the [DeskPro 386 ROMs](/devices/pc/rom/compaq/bios/deskpro386/) and system boards.
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I also have the hard-to-find **COMPAQ Technical Reference Guide** for the DeskPro 386/25 (Vol. 1), which I'll post
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at a later date.
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COMPAQ Portable III
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---
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Reportedly intended to be an 80386-based machine, the Portable III was first released in 1987 as a 12Mhz
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80286-based system.
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PCjs also has information about [COMPAQ Portable III ROMs](/devices/pc/rom/compaq/bios/portable3/).
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**Model** | **Price** | **CPU** | **Options**
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:-------- | :-------- | :---------------- | :----------------------------
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| $5000+ | 12Mhz 80286 | 640Kb RAM, 1 FDD, 20-40Mb HDD
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COMPAQ Portable 386
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---
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[TBD]
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COMPAQ 386/20e
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---
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Released in late 1988. For use with MS-DOS 3.31.
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COMPAQ SLT Series
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---
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From [Wikipedia](https://en.wikipedia.org/wiki/History_of_laptops#Compaq_SLT.2F286): "The COMPAQ SLT/286 debuted
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in October 1988, being the first battery-powered laptop to support an internal hard disk drive and a VGA compatible
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LCD screen. It weighed 14 lbs."
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COMPAQ LTE Series
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---
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First model in 1989.
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Also see [Wikipedia](https://en.wikipedia.org/wiki/Compaq_LTE).
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### COMPAQ LTE 286
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Various models, such as the [Model 40](http://www.overclockers.com/compaq-lte-286-model-40/).
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### COMPAQ LTE 386
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*[@jeffpar](http://twitter.com/jeffpar)*
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*February 24, 2016*
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94
_posts/2016-02-24-remembering-compaq.md
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94
_posts/2016-02-24-remembering-compaq.md
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@ -0,0 +1,94 @@
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---
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layout: post
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title: Remembering COMPAQ
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date: 2016-02-24 14:00:00
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permalink: /blog/2016/02/24/
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---
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IBM is obviously the company everyone thinks of first when we talk about the IBM PC -- after all, IBM is right
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there in the name. And they designed the thing. So IBM deserves lots of credit, especially the folks who worked
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in Boca Raton at IBM's Entry Systems Division in the early 1980's.
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However, IBM was a huge company that existed *before* the IBM PC and which still exists today; they had some built-in
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advantages. The PC era also saw a lot of companies spring up from nowhere and then disappear just as quickly.
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Some of them didn't do anything particularly innovative or noteworthy -- they probably just wanted to ride the PC wave
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and make some easy money in the process.
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I think one of the more exceptional companies from that era is COMPAQ. It's easy to dismiss COMPAQ as just another
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"copy-cat" operation, but I think it's a mistake to dismiss any company in the PC business as simply "copying" or
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"cloning" the IBM design. Companies like COMPAQ were really in the *compatibility* business.
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Innovation in the PC industry would not have been as rapid and diverse if IBM had been the only supplier of
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compatible machines and accessories. And IBM probably would have continued some of the monopolistic practices it had
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perfected in the mainframe era, like exclusive service contracts. That might have been a win for IBM, but it almost
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certainly would *not* have been a win for customers.
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In 1982, the founders of COMPAQ took a big gamble, by reportedly investing around a million dollars to create
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system software (ROM BIOS) that mimicked IBM's without infringing on it. I don't know if COMPAQ pioneered the concept
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of "clean room" design, where the engineers designing and coding have no direct contact with the hardware and software
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they're cloning, but they were certainly successful.
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But that wasn't COMPAQ's most important contribution. That was just the price they had to "pay to play." Armed with
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compatible hardware and software, COMPAQ proceeded to innovate in ways that IBM did not.
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Look at COMPAQ's first product: the COMPAQ Portable. For starters, it was *portable*. And unlike
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IBM machines, it didn't force you to choose between a higher-quality text-only (MDA) display or a lower-quality
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graphics-capable (CGA) display. COMPAQ improved on IBM's mutually-exclusive display choices by creating a monochrome
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display that could display both high-quality text *and* graphics.
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IBM released their own portable unit a year later, but it looked suspciously COMPAQ-like, and it lacked COMPAQ's
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innovative display.
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That tradition of innovation at COMPAQ continued for many years. Sometimes they even seemed *more* concerned about
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compatibility than IBM did. For example, faster machines sometimes broke speed-sensitive floppy-based copy protection
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schemes, which COMPAQ tried to avoid by automatically *slowing* the machine down whenever a floppy drive was spinning.
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To my knowledge, IBM never bothered with such a feature -- maybe IBM was simply being pragmatic, or perhaps they were
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just a little arrogant, operating on the theory that if the universe revolves around IBM, then the planets will
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simply realign *themselves* (translation: software vendors will release new versions if they want to remain IBM-compatible).
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Sadly, COMPAQ was ultimately absorbed by another behemoth -- Hewlett Packard -- and then simply disappeared. Today,
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all we have are the memories.
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### Speaking of Memories
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In particular, Read-Only Memories: we have precious few of those, too. I finally obtained
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a [ROM Dump](/devices/pc/rom/compaq/bios/portable/) from COMPAQ's first machine, the COMPAQ Portable, but I had to buy
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a system board on eBay to get it. Considering all the effort (and money) that COMPAQ invested in writing that code,
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you would think those things would be memorialized a bit better.
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Looking ahead to the day when PCjs will be able to simulate the original COMPAQ Portable, I thought it would be a good
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idea to create my own roughly chronological list of [COMPAQ Machines](/devices/pc/machine/compaq/) from the 1980s,
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since they are all machines I would like to see PCjs eventually support:
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+ COMPAQ Portable
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+ COMPAQ [Portable] Plus
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+ COMPAQ DeskPro
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+ COMPAQ DeskPro 286
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+ COMPAQ Portable 286
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+ COMPAQ Portable II
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+ [COMPAQ DeskPro 386](/devices/pc/machine/compaq/deskpro386/)
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+ COMPAQ Portable III
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+ COMPAQ Portable 386
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+ COMPAQ 386/20e
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+ COMPAQ SLT Series (SLT/286)
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+ COMPAQ LTE Series (LTE 286, LTE 386)
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It's hard to stop at this point, because PCjs supports the 80386, and COMPAQ produced other 80386-based systems,
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like those in the "LTE Lite" series. But I think I need to stick my original plan and draw a line at the end of the
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1980s.
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### Regarding The COMPAQ Name
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As best I can tell, COMPAQ preferred to print its company name in all-caps, so that's my practice as well.
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However, it seems that sometime between the release of [COMPAQ MS-DOS 3.10](/disks/pc/dos/compaq/3.10/) and
|
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[COMPAQ MS-DOS 3.31](/disks/pc/dos/compaq/3.31/), there may have been a shift in policy. Both products still
|
||||
called themselves `The COMPAQ Personal Computer MS-DOS`, but in 3.31, the copyright string changed to
|
||||
`Compaq Computer Corp.`
|
||||
|
||||
Their all-caps practice also extended to at least *some* product names (eg, the `COMPAQ DESKPRO`), but I'm not sure
|
||||
how strict they were, and I'm decidedly less so, which is why I use the name `COMPAQ DeskPro`.
|
||||
|
||||
*[@jeffpar](http://twitter.com/jeffpar)*
|
||||
*February 24, 2016*
|
||||
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