Questions tagged [80386]

Intel's 80386 processor, alternatively known as the i386 or 386. Use only for questions specifically about the processor; DO NO USE to mean ‘386-class machine’.

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How did AMD Am386 and Am486 outperform Intel's version of the same microprocessors?

This question is related to a previous one that has been asked here before (How did AMD's 386 and 486 perform like Intel's newer generation?) My question is-two fold: a) When AMD "...
interested22's user avatar
10 votes
3 answers
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Why did Steve Jobs choose the Motorola 68030@25 MHz for the first NeXT Computer in 1988 and not an Intel 80386DX@25 MHz processor?

Was the reason because he knew the 68K from the Macintosh, or were there other reasons that spoke in favor of the 68030 and the additional 68882 floating-point coprocessor? The i386, along with a 387 ...
Coder's user avatar
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14 votes
0 answers
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Is it possible to trap 387 FPU opcodes on a 287 connected to a 386?

The 8087 and 287 FPUs were designed before the IEEE 754 standard was released. Because of this, they contain some instructions which are not compliant with it. When the 387 was released in 1987, it ...
DarkAtom's user avatar
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24 votes
4 answers
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How can a 32-bit x86 CPU start with reset vector 0xFFFFFFF0 even though it starts in 16-bit real mode?

As far as I know, x86 CPUs start up in 16-bit 'real' mode (maybe some don't). The reset vector is 0xFFFFFFF0 (in most CPUs and in this context) In this 16-bit real mode, we can only access 16 bit ...
Example person's user avatar
12 votes
1 answer
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What 386-specific features did Linux use?

There is an interesting discussion about the early days of Linux at https://www.abortretry.fail/p/the-path-to-linux that includes some of the exchanges between Torvalds and Tanenbaum. One that caught ...
rwallace's user avatar
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17 votes
2 answers
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When did the 386 overtake the 286?

The Intel 80386 was released in 1985, but was initially expensive, and took a long time to fully displace the earlier 80286 from the market; subjectively, I remember significant numbers of 286 ...
rwallace's user avatar
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5 votes
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How do I best simulate a 80386? [closed]

I have used emu8086 to simulate the Intel 8086 before. I like that it allows me to view the opcodes, the data in the registers in a very user friendly way. What simulators are available for the 80386?...
Hex Heager's user avatar
5 votes
3 answers
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Does Intel Inboard 386/PC work on XT clone systems?

I don't have an Intel Inboard 386/PC, but I have a plan to buy it in the future. When I read its manual, there was no support for XT clones. It says: Install the Inboard 386/PC only in the computers ...
Sung's user avatar
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6 votes
1 answer
319 views

XMS function 0Ch "Lock Extended Memory Block"

I have a question about this function that has bugged me for years, so I decided to let this community a try :) So, this function supposedly locks a XMS extended memory block in place, and returns an ...
Vasil Daskalov's user avatar
7 votes
3 answers
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Identifying motherboard and CPU

Anyone ever see a CPU with this identification? Or does anyone know what kind of motherboard this is? Thanks
Jeremy Hubbard's user avatar
13 votes
2 answers
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How is the ‘Coprocessor segment overrun’ exception supposed to be handled?

The Intel 80386 CPU didn't have an on-board x87 FPU (maybe with the exception of some non-Intel clones). It was, however, able to use either a 80287 or 80387 as an external FPU. When the x87 FPU ...
DarkAtom's user avatar
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23 votes
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How were the test registers used on the i386 and the i486?

The Intel 386 and 486 CPUs (and some clones too) had some test registers (TR3–TR7) which were used to test features like the TLB and caches. Starting with Pentium, these were replaced with MSRs (Model ...
DarkAtom's user avatar
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11 votes
3 answers
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What was the "32-bit" ISA bus (connector) extension for 80386 PCs?

I have a question which is similar to another question on this site: When I was a child 386 PCs came up. When buying a PC, you could read in the technical data how many 8- and 16-bit ISA slots were ...
Martin Rosenau's user avatar
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What's the heritage of 80286? [closed]

80186 introduced some instructions for HLL features. 80286 introduced some instructions for protected mode, and provided some multitasking ability with external MMU which was never intended for PCs ...
Schezuk's user avatar
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12 votes
2 answers
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Intel 386 multiply bug

Some early models of Intel 80386 processors had a bug with 32-bit integer multiplication. Those which were found to have the bug were marked "16-bit S/W ONLY" (not sure what S/W is supposed ...
DarkAtom's user avatar
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19 votes
2 answers
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How did AMD's 386 and 486 perform like Intel's newer generation?

AMD really started to come into its own as a competitor to Intel around the time of the Intel 80486 introduction. AMD countered Intel by shipping the popular (at least with PC enthusiasts) Am386-40, ...
Brian H's user avatar
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7 votes
1 answer
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80387 transistor count

In 1985, Intel released the 80386, a particularly complex and sophisticated microprocessor for its day, consisting of 275,000 transistors, a rather large number for the day. How many transistors went ...
rwallace's user avatar
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2 votes
2 answers
457 views

First 386 PC on sale in the UK

In the early days of personal computers, there was something of a delay in the technology crossing the Atlantic, and when American computers did arrive in the UK, they tended to be expensive relative ...
rwallace's user avatar
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1 vote
1 answer
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How to configure HDD controller for CF in CHIPS LeAPset 117 (R1.09) bios

I'd like to use Compact Flash with 2,5" IDE adapter in i386 laptop. The bios is CHIPS LeAPset 117 (R1.09) and it requires specific configuration for HDD in order to work. I have 4GB CF card, where I ...
Bartek Malysz's user avatar
6 votes
2 answers
2k views

Is solder-on memory upgrade an option here and how to check it

I have this system with 2MB onboard RAM, but I noticed there are additional soldering pads to the right from memory chips (NEC 424400-80L, but there are also TOSHIBAs TC511664JL-10 on daughter board ...
Bartek Malysz's user avatar
3 votes
1 answer
715 views

What is this socket for in 386 notebook motherboard

What is this socket for on 386 motherboard? I have no manual, no documentation and no resources readily available for this machine (Commodore C386SX-LT). Source: Probably oldcrap.org Close-up: ...
Bartek Malysz's user avatar
8 votes
5 answers
3k views

Connect Ethernet via Parallel or Serial in old laptop

Is it possible to connect an old 386 machine to network (ethernet)? It has only parallel and serial ports. I'm not expecting much, just planning to use it as a remote terminal. The machine in question ...
Bartek Malysz's user avatar
19 votes
2 answers
4k views

What are these weird long ISA slots on this 386 board? (not VLB)

In this image, you can see, from the right, a 16-bit ISA slot (occupied by a controller card), an 8-bit ISA slot, four more 16-bit ISA slots, and two of these strange slots that look like a 16-bit ISA ...
robbie's user avatar
  • 321
0 votes
0 answers
204 views

Portable 386 that only ever beeps continuously; no video

I've acquired a late-80s portable 386 with builtin LCD in unknown working state. It only ever beeps continuously on boot, with no picture on either the built-in LCD or an external VGA-connected ...
incanus's user avatar
  • 109
2 votes
3 answers
903 views

386 laptop: reads MBR, cannot boot DOS 6.22

I am trying to boot 386 laptop from a CF card. I've prepared image by installing DOS 6.22 in VirtualBox, and then burning image to a CF card. Image boots just fine in VirtualBox. CF card with the ...
BarsMonster's user avatar
2 votes
2 answers
1k views

How much PSU power do I need for an AMD 386DX-40 computer?

Just picked up my first retro PC the other day. Unfortunately, it's lacking a PSU so I need to find one. What kind of a PSU (in terms of wattage) do I need to comfortably run an AMD 386DX-40 system? ...
Violet Giraffe's user avatar
2 votes
2 answers
797 views

Parity error under DOS

I'm facing a Parity Error problem on my new 486er DOS Retro PC. Every now and then, a running software crashes with a Parity Error output on screen. This happens for different software so I think the ...
Ziagl's user avatar
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26 votes
4 answers
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How much RAM could one put in a typical 80386 setup?

I read on Wikipedia that 80386 could theoretically handle 4GiB of RAM. Knowing how long ago that was, I find it impossible to believe that anyone could actually connect as much to the CPU. So, given ...
d33tah's user avatar
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19 votes
2 answers
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Examples of operating systems using hardware task switching of x86 CPUs

Intel IA-32 architecture a.k.a. x86 offers hardware task switching capabilities since 80386. It includes TR (task register), memory segmentation features such as Task State Segment, task gates, call ...
Grigory Rechistov's user avatar
30 votes
3 answers
7k views

386SX, NES and how much did data lines really cost anyway?

In 1988, Intel introduced the 80386SX, most often referred to as the 386SX, a cut-down version of the 80386 with a 16-bit data bus mainly intended for lower-cost PCs aimed at the home, educational, ...
rwallace's user avatar
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3 votes
2 answers
2k views

USB ports for a 486 laptop (pccard 16bits)

I have an old laptop 486 with PhoenixBIOS which supports PC card 16bits( PCMCIA II/III). I am thinking about the possibility of adding a pccard 16bits with USB ports, mainly to read usbsticks or ...
Daniel Perez's user avatar
4 votes
1 answer
554 views

Operating systems (on support or recent) to install on a i486 processor computer [duplicate]

What operating systems would you recommend for this type of hardware? Though I keep the question text generic because answers can work for many others, but my specific case is a Laptop Siemens ...
Daniel Perez's user avatar
2 votes
1 answer
866 views

What make and model is this 386 mainboard?

I have received a 386 mainboard with OPTI chipset. Possibly an early model, since it does not support cache. The chipset is labeled "82C381P" and "Chipset2".
Arne's user avatar
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28 votes
2 answers
8k views

The start of x86: Intel 8080 vs Intel 8086?

Why is it said that all modern Intel processors of the x86 family are said to descend from the Intel 8086 and not the Intel 8080? From the Wikipedia article on the Intel 8086, The 8086 gave rise to ...
Evan Carroll's user avatar
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6 votes
1 answer
812 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. ...
AlphaCentauri's user avatar
11 votes
6 answers
2k views

When did the tower form factor appear and when did it become popular?

Essentially, my question is there in the title. Tower cases are commonplace these days, and probably are the "default" form factor for personal computers (or at least were, before they were surpassed ...
Tobia Tesan's user avatar
3 votes
2 answers
361 views

IBM PS/2 Model 53 Not Powering On

I bought a PS/2 with the intent of robbing it's case for a restomod project, but since that is on the backburner right now I decided to see if it would work. When I flip the power switch, the PSU ...
Zekial's user avatar
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6 votes
1 answer
525 views

What exactly were those 808X computers that would switch to 80386 upon Ctrl-Alt-Del?

A while ago I've been told that some generic-brand PC, (yet packed on an IBM5150 case) had the ability to become a 80386 upon pressing Ctrl-Alt-Del (warm reboot) ? I guess there might have been (for ...
Eric Cartman's user avatar
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12 votes
3 answers
549 views

Pair Am386 with i387

I've got a motherboard with a Am386/DX processor. I've also got an Intel 387 coprocessor. Is it possible to use the Intel 387 that I've got together with the Am386 or do I need a coprocessor from AMD?...
Seeseemelk's user avatar