Skip to main content

Questions tagged [intel]

Retrocomputing hardware and software created by Intel.

Filter by
Sorted by
Tagged with
11 votes
1 answer
389 views

What was the 6-bit length instruction(s) in the Intel iAPX 432?

The iAPX 432 was arguably the most complex processor architecture ever and a commercial failure for Intel. It was a stack machine with no visible general-purpose registers. It had hardware support ...
DrSheldon's user avatar
  • 16.3k
15 votes
1 answer
3k views

What's the story behind the "mysterious" 486DX3?

As I was skimming through an old MS-DOS game's README, I stumbled upon this: Therefore, we reccomend a newer 486-100 or better, preferably with a large external cache. Best performance will result ...
aybe's user avatar
  • 7,102
9 votes
2 answers
366 views

What floating point libraries were written to meet the IEEE 754 standard before it was accepted in 1985?

The IEEE 754 floating point arithmetic working group began in 1977 and was formally accepted in 1985. One of the original driving factors of the standard itself was Intel who wanted a standard to go ...
Adam Hyland's user avatar
5 votes
1 answer
583 views

Did the i186 use interrupt 6 for invalid opcodes?

I don't recall where from but at some point I was under the impression that the Intel 186 processor used interrupt 6 for invalid opcodes. However, there's the HP 95LX that uses a NEC V20. NEC V20/V30 ...
ecm's user avatar
  • 972
6 votes
1 answer
571 views

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
7 votes
0 answers
88 views

iRMX bootsector on a iRMX partition how to clone?

I have an old year 2000 instrument which has a 340MB hard drive. I am trying to clone the hard drive but I am having major issues. First the instrument uses iRMX and MSDOS the bios is using the CHS ...
mpcengineer's user avatar
0 votes
1 answer
154 views

What if ATX 12v P4 power connector was introduced 4 years earlier? [closed]

AT power supply handled +5 and +12 volts, +5 for ISA and processors, +12 for motors in disk drives. In 1995 486DX2 was introduced with 3.3V core, so it derived that from a simple but inefficient ...
Ivan Borsuk's user avatar
13 votes
3 answers
539 views

How much extra die area did a CMOS CPU take?

Starting in the late seventies, the microchip industry generally switched from NMOS to CMOS, primarily because CMOS circuits use less power, though they also have other advantages like more noise ...
rwallace's user avatar
  • 62.7k
14 votes
1 answer
1k views

Intel "Kernel processor" or "OS Kernel"

I used to have an Intel data book from 1981. I gave it away to a friend, and he probably also lost it along the way. In this book there was a data sheet for a component called "OS Kernel" or ...
chthon's user avatar
  • 700
18 votes
3 answers
2k views

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
  • 62.7k
4 votes
1 answer
241 views

Are there multiple models of the Intel 8089 IOP?

As far as I'm concerned there is only one model of the Intel 8089 (the D8089A-3). I am not able to find any information on this. While the 8086,8088 and 8087 use the scheme of the last number (-3 in ...
juffma's user avatar
  • 195
8 votes
3 answers
2k views

Why was the size of the 1989 Intel i860 (aka 80860) memory bus 64bit?

On Wikipedia I have read the i860 from 1989 memory bus was at least 64bits wide. (It is the first CPU the Windows NT kernel was running on.) I think even 10 years later (1999) most desktop CPUs were ...
zomega's user avatar
  • 5,372
5 votes
3 answers
1k views

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
  • 509
28 votes
3 answers
4k views

Why are the Intel 8080's rotate instructions called opposite to intuition?

The Intel 8080 has two pairs of instructions for rotating the value of the accumulator -- RLC/RRC and RAL/RAR. One of them shifts the 8 bits in the accumulator circularly, writing out into the carry ...
Danya02's user avatar
  • 383
6 votes
1 answer
638 views

Why did the 8085 multiplex data with the low address byte?

Intel’s 8085 used bus multiplexing to stuff more functionality into 40 pins than would otherwise be possible. One of those pins, ALE, signals when the AD0…7 pins are outputting the low byte of the ...
Jacob Krall's user avatar
  • 2,289
4 votes
1 answer
227 views

Why 8086/8088 has OF in a high Flags byte?

In 8086, OF is put not into low Flags byte as other flags but separated in the second (high) byte. This is followed then in all the x86 line. Beside the possible historical reasons, this looks highly ...
Netch's user avatar
  • 530
5 votes
3 answers
1k views

Why has the Intel Itanium failed to take on the world? [closed]

Last summer, the Itanium has finally been discontinued, twenty years after its release. It was a promising technology, but in the end it turned out to not really be the case. Beside a few niche ...
aybe's user avatar
  • 7,102
6 votes
3 answers
751 views

Did Intel syntax for x86 assembly come from an Intel assembler?

I'm wondering where the so-called Intel syntax for x86 assembly came from. Did Intel release their own assembler for chips like the 8086 or do we just mean the syntax they used in the manuals?
Anthony's user avatar
  • 455
20 votes
2 answers
4k views

Did any notable product use Intel's first RAM?

The 3101 SRAM was Intel's first product. At $99.50 for 64 bits, it had enough memory to store the characters expensiv. (Sorry, the final e costs extra.) Is there a record of any product using it?
DrSheldon's user avatar
  • 16.3k
12 votes
1 answer
2k views

Which endian was the Intel 4004?

The Intel 4004 had 4-bit buses and data words, but the program counter and code address space was 12 bits. Was the 4004 little endian (like all of Intel's later microprocessors and microcontrollers) ...
DrSheldon's user avatar
  • 16.3k
1 vote
1 answer
369 views

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
  • 3,754
3 votes
0 answers
188 views

Scaling compute times to a Pentium III 700 MHz [closed]

According to a competition programming site, where users can submit single source files to be compiled and run, "programs are run on a modern processor but times are scaled to a 700 MHz Pentium ...
qwr's user avatar
  • 315
3 votes
1 answer
607 views

How much RAM was sold each year in the 1970s?

I'm trying to get an idea of the quantitative parameters of the computer industry in the era that saw the rise of personal computers. Of course, the industry as a whole was old by then; companies like ...
rwallace's user avatar
  • 62.7k
19 votes
2 answers
3k views

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
  • 60.8k
7 votes
1 answer
656 views

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
  • 62.7k
2 votes
1 answer
780 views

Intel vs Motorola device communication protocols

On this page about "An S-100 68000 CPU Board" it is said: From a hardware perspective there are some very significant differences how Intel and Motorola CPU's talk to the world. Somewhat ...
rwallace's user avatar
  • 62.7k
2 votes
0 answers
159 views

advice for retrieving functions and tables from intel 8061/8065 bin file (reverse engineering) from Ford EECV ECU

I have under my disposal some Ford EECV bin files and my goal for the next few weeks is to retrieve the functions and tables and plot them out before going onto DIY hardware . . Does anyone know which ...
Jingyi Tay's user avatar
33 votes
4 answers
10k views

Intel CPU bug in the 90s

My teacher who teaches "Logic" at the university told us a story about Intel processors, which goes: "In the 90s, Intel had a bug in the calculation of mathematical functions like sine ...
gomd's user avatar
  • 433
21 votes
5 answers
3k views

How and why did Intel make the PCI bus "CPU Agnostic"?

Intel invented the original 32/64-bit PCI bus in the early 1990s to replace the decade old ISA bus used in PC's. It was immediately popular (in comparison to Micro Channel or EISA), being both faster ...
Brian H's user avatar
  • 60.8k
4 votes
1 answer
479 views

Instructions added with the Intel 80286 [closed]

The 80286 processor added these instructions: ARPL, VERR, VERW, LAR, LSL, SMSW, SGDT, SIDT, SLDT, STR, LMSW, LGDT, LIDT, LLDT, LTR, CLTS. To help understand how this was implemented I am looking for ...
Single Malt's user avatar
  • 1,859
13 votes
1 answer
2k views

Intel processor transistor type evolution

The Intel 4004 used MOS (metal–oxide–semiconductor) transistors. What has been the transistor types used in Intel processors onwards from the 4004 to 8085 to the x86 family of instruction set ...
Single Malt's user avatar
  • 1,859
0 votes
1 answer
206 views

Carry flag in the Intel 8008

Datasheet for the Intel 8008 CPU mentions that the Carry (C) flag is affected with the logic operations (AND, OR, XOR), but it does not make any sense. I believe Carry will be zeroed, but I have no ...
Martin Maly's user avatar
  • 5,575
3 votes
1 answer
503 views

Intel 8008 stack behavior

Intel 8008 CPU has an internal stack, implemented as an 8 x 14-bit scratchpad. How does it work exactly? Is there any "invisible 3-bit stack pointer"? I want to know what happens when the ...
Martin Maly's user avatar
  • 5,575
8 votes
0 answers
312 views

Undefined opcodes for the Intel 8008 CPU

What happens when I8008 CPU reads the "undefined" opcode (22h, 2Ah, 32h, 38h, 39h, 3Ah; or in octal 042, 052, 062, 070, 071, and 072)? Are these opcodes evaluated as a NOP instruction, or ...
Martin Maly's user avatar
  • 5,575
-3 votes
2 answers
642 views

Should I install Gentoo i586 packages on my PC? [closed]

I've recently commenced revitalizing an HP Pavilion Slim. She's running an Intel Pentium, x86_64. I thought I'd give Gentoo a go because I've found it very appealing and as a Bedrock user I wanted to ...
Bobbbay's user avatar
  • 95
5 votes
1 answer
298 views

Do all Intel Celeron processors support "FCOMIP"? [closed]

I am interested, did all Celeron processors support the FCOMIP instruction? I've made a compiler for my programming language and it uses FCOMIP for every floating-point comparison. I've noticed that ...
FlatAssembler's user avatar
2 votes
1 answer
497 views

Are all Slot 1 motherboards compatible with Coppermine?

I want to put together a Pentium III tower using a beautiful Coppermine SL3XL CPU I found with a Slot 1 form factor. However, I noticed that many slot 1 motherboards do not officially support ...
robbie's user avatar
  • 321
6 votes
2 answers
1k views

What’s the last x86 CPU that didn’t place a limit on the size of a single instruction?

Although useless, it’s widely known the first Intel and derivative CPUs like the Z80 didn’t set a limit on the instruction size. This means that it was possible to fill the whole RAM/ROM with a single ...
user2284570's user avatar
41 votes
4 answers
14k views

Is it true that Pentium III was faster than its successor Pentium 4?

My friend told me that earlier iterations of the Pentium 4 were not as fast as the Pentium III, but he didn't have sources. Is it true that the Pentium III was faster than its successor Pentium 4?
May Teresa'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
21 votes
2 answers
8k views

Why did Socket 3 have more pins than needed for the 486?

Intel's Socket 3, used for 486 processors, was a 19×19 pin grid array socket. However, all compatible processors, to my knowledge, used 17×17 PGA packages. What was the point of the extra pins around ...
Hearth's user avatar
  • 725
17 votes
2 answers
1k views

Which computers used the Intel 82786 graphics chips, and what sort of commercial success did that chip attain?

In the late 1980's, Intel offered the 82786 graphics chip, with specific support for windowed environments. I remember it being covered in Byte magazine, but don't remember seeing any applications of ...
mschaef's user avatar
  • 4,836
10 votes
2 answers
2k views

First x86 Software Development Manual

These manuals are now called “Intel® 64 and IA-32 Architectures Software Developer Manuals”, and the current version is 71. What was the original name of this manual and when was it released?
Single Malt's user avatar
  • 1,859
92 votes
10 answers
34k views

How much better was DEC Alpha than contemporaneous x86?

The DEC Alpha, released in 1992, seems like an early implementation of a fully 64-bit microprocessor architecture. Its release led to quite a bit of both marketing hype and genuine vendor support in ...
Brian H's user avatar
  • 60.8k
15 votes
1 answer
2k views

What is the history of the Intel 8275 video controller?

The highly popular at the time build-it-yourself home computer Radio 86RK, designed in the Soviet Union, contained a rather mysterious video controller chip КР580ВГ75. It had a high end, feature rich ...
h22's user avatar
  • 413
5 votes
3 answers
1k views

Need circuit - manual step-by-step clock for 8086/8088

I finally bought a ceramic 8086-1 (from ebay, from China - I'm not sure that it is not fake chip) and 8284 (it make the necessary synchronization signal for the processor from the crystal). Now I ...
Alex's user avatar
  • 471
0 votes
2 answers
1k views

What 486 motherboard is this, with American Megatrends BIOS identifying is DPAQ-6156-043090-KF?

I've got an early 486 motherboard that doesn't seem to have a manufacturer name or FCC number on it and I'm having trouble identifying it. I've placed some photos of the motherboard in this Imgur ...
yanagibashi's user avatar
29 votes
3 answers
7k views

Why did Intel abandon unified CPU cache?

When Intel introduced the 80486 in 1989, they included their first on-chip cache, ostensibly to compete better with Motorola, who had been including on-chip caches for 5 years (MC68020, 1984). Unlike ...
Brian H's user avatar
  • 60.8k
7 votes
1 answer
1k views

What was the first Intel x86 processor with "Base + Index * Scale + Displacement" addressing mode?

As the title says, what's the first x86 processor from Intel that supports the following addressing mode? mov %reg, 8(base, index, 4) ^^^^^^^^^^^^^^^^^ where the content of %reg will be ...
iBug's user avatar
  • 199
24 votes
2 answers
7k views

What was the last x86 CPU that did not have the x87 floating-point unit built in?

This Wikipedia page says the following: Most x86 processors since the Intel 80486 have had these x87 instructions implemented in the main CPU So the above quote implies that some CPUs that were ...
user12280's user avatar
  • 293