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Questions tagged [80286]

For questions about the Intel 80286 16-bit microprocessor

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Which operating systems for 80286 computers allowed a process to use more than 128k data?

Out of all the operating systems for the 80286 processor I found, only two make use of the protected mode's ability to load more than one segment for text and one for data. These are MS-DOS (through ...
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What 286 chipsets support UMBs?

I read in some forums that some 286 boards support UMBs and thus can load drivers and TSRs into the upper 384 KiB of conventional memory. What chipsets support this and do I need special drivers?
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How do you put a 286 in Protected Mode?

From the Art of Intel x86 Assembly, Page 149, The 80386 added four control registers: CR0-CR3. These registers extend the msw registers of the 80286 [...] The book says earlier that, The 80286 ...
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80286 pricing and availability

Most information online states that the 80286 (or iAPX 286 as it was initially known) was first available in February 1982. But information about it from this time is hard to come by, and famously it ...
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1answer
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How to diagnose a failed capacitor on the mainboard?

My Fox II 286 mainboard just blew a capacitor. I haven't yet powered it on, so maybe the cap was bad. How can I diagnose this problem, and eliminate other bad caps?
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2answers
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What DOS software can I test a QIC-02 tape drive with?

I got a Wangtek 5150EQ tape drive that connects to a dumb (made of a bunch of 74-series logic chips) 8-bit ISA tape controller card. The controller card has a bunch of DIP switches which I used to ...
6
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1answer
404 views

First 80286 Based Computer

The 80286 was released in early 1982. The IBM PC AT, which used it, was released in late 1984. Two and a half years is a long time to design a new computer that is a fairly modest upgrade on existing ...
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2answers
154 views

Jumper and switch settings for 286 Suntac mainboard

I have a 286 mainboard here, which is I think very similar to this one here at stason.org. Below is an overview image, and a link to a album with details. However there are still some discrepancies, ...
5
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1answer
189 views

What kind of SIMMs can 286 PCs use?

I have a 286 Board (Octek Fox II 286) which takes up to four 30 pin SIMM modules. The manual however (http://www.minuszerodegrees.net/manuals/Octek%20-%20FOX-II%20286%20(12_16%20MHz%20versions).pdf) ...
5
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1answer
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Manual or jumper settings for mainboard PWA-286C

I have an old mainboard, type PWA-286C, running a 10 MHz Intel 80286. I have no manuals, so I am looking for documentation on it. I am especially wondering if there is a connector for the real time ...
5
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1answer
285 views

What was the fastest third party FPU?

For both the x86 and SPARC based machines, it was possible to get not only FPUs installed as a separate, discrete IC, but also third party FPUs. In particular, I've read about Weitek on Wikipedia. ...
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Replacing 80286 with 68000

Suppose you wanted to take a 286 PC and replace the CPU with a 68000, not at the initial design stage, but actually modifying the finished machine, on the theory that they both have 24 bits of address ...
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Is a Heatsink Needed for an Intel 80286?

I noticed my IBM XT 286 has no heatsink on the CPU nor a fan of any kind (only the PSU has a fan). I realize this was fine when it was built, but for longevity purposes, should I put a heatsink on it? ...
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4answers
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What conventions and language extensions did people use to program the 8086 and 80286?

The 8086 is a 16 bit processor with a 20 bit segmented address space, famous for being used in the IBM PC. It is also infamous for being tricky to program for. I am currently writing what is ...
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4answers
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How did the Apple II forward binary instructions to the Z80 software card with CPM?

Microsoft produced the Z80 Softcard for the Apple II enabling it to run CPM and many Z80 binary programs. This seems to be an unthinkable achievement. (For a kid who had an Apple IIe but was only a ...
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3answers
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What is the infamous instruction LOADALL on the 80286 and what was it used for?

This undocumented instruction existed in the 80286 and, I believe, the 80386. I think it was added while debugging the chip, so the engineers could quickly put the processor into any state and test it ...
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3answers
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How can I access an old pre-IDE disk?

I have a wonderful Zenith SupersPORT 286 laptop (ZWE-0200-40) whose power circuitry seems faulty and it no longer powers up. I have useful material on the disk which I'd like to extract. The disk (a ...
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3answers
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80286 can switch from real mode to protected mode - but why not back?

It's been a while, but I've read in a system programming book that you could switch your Intel 80286 CPU from the normal real mode to a more powerful protected mode. I clearly remember that they said ...