All Questions

3
votes
0answers
29 views

Tannenbaum paper on constants in ISAs?

I see many references to a paper by Andrew Tanenbaum that demonstrated the vast majority of constants would fit into 13-bits, and I seem to recall it being in my university text on CPU design. However,...
7
votes
3answers
272 views

Why do Early DRAMs (e.g. 4116) have a negative Column Address Set-up Time?

Early DRAMs have a multiplexed address bus. Briefly speaking, to access a word, one needs to... Put the row address on the bus, and latch it using the falling edge of /RAS signal. Put the column ...
12
votes
7answers
746 views

Did any system natively use 3-bitplane graphics?

Computer and game consoles switched gradually from single-bitplane graphics (2 colours per character) to 2-bitplane graphics (4 colours per character), to eventually 4-bitplane graphics (16 colours ...
57
votes
7answers
15k views

How were the first ZX Spectrum games written?

Being a child of the 80s I loved my ZX Spectrum, did my best to learn BASIC but I felt like the games I was playing (Jetpac, Dizzy, Renegade etc) were perhaps not written using BASIC. I wondered: how ...
8
votes
2answers
231 views

What connection exists between Facit AB and Sharp on the MZ-800 computer?

Facit used to be a very successful Swedish company manufacturing mechanical calculators that quickly went down to its final demise by not being able to adapt to the shift towards electronic ...
13
votes
3answers
379 views

How can I run COMIT code?

I recently learned about the existence of COMIT, which was the first string processing language. It's very old (1957), but it was used a lot in the first 10 years it was around, mainly in academic ...
22
votes
17answers
6k views

Was self-modifying code possible using BASIC?

Was self-modifying-code possible using BASIC? Parameters: On commonly affordable home-computers before 1984 Code that changes its own instructions while it is executing Using BASIC only Not using ...
46
votes
4answers
9k views

What did the 8086 (and 8088) do upon encountering an illegal instruction?

Preface: This question does in part intersect with Use of undocumented opcodes, but targets especially the 8086 instruction handling. I was reading Tanenbaum's "Operating Systems, Design and ...
6
votes
4answers
1k views

High-end PC graphics circa 1990?

I remember CAD being a major driver for PCs with high-end graphics cards; specifically AutoCAD was rising quickly in popularity around 1990 as PCs were able to compete with very costly CAD ...
5
votes
4answers
172 views

Getting Music Functioning for Raptor: Call of the Shadows (1994)

I can't get the music audio working for the 1994 version of Raptor. Does anyone know how I can remedy this? I'm not sure if this is the correct forum for this question, but here goes. I have an ...
2
votes
1answer
183 views

Capacitor replacement on European 220 volt Mac 512K And Plus

I have had two Macs, a 512K and a Plus, in storage since they failed the smoke test in a spectacular manner a few years back. I have finally learned how to solder and de-solder, so I think its time to ...
1
vote
2answers
163 views

Will the circuit work normally if different chip speeds (eg 8088-2 and 8255-1)

Old processors came out with support chips. That is, there was a family - the processor and its chips. Over time, the same kits came out with higher frequencies. Will the circuit work properly if ...
7
votes
2answers
383 views

Is there data for programming language popularity pre year 2000?

Besides the TIOBE Index, which ranks programming language popularity by search engine hits and seems to have data reaching back to the year 2001, are there other sources with some form of measure for ...
5
votes
1answer
198 views

Where to find a ROM dump for the Atari ST cartridge 'ACTION'

Back in the day I owned a couple Atari ST, I used a cartridge based program for writing video games. It was called "ACTION" Does anyone remember this program or even better, know where I can get a ROM ...
4
votes
4answers
954 views

Why does this Apple //e drops into system monitor when booting?

I recently purchased an Apple //e online as well as a BMOW Floppy Emu in order to emulate some disk images. After working with it successfully for awhile, this monitor consistently appeared in lieu of ...
1
vote
1answer
95 views

Software Failure after RAM upgrade Amitek Hawk

I have Amitek Hawk for my A1200, the board came with wrong RAM and apps were crashing with 8003 Guru error. After contacting the seller I was told by mistake wrong SIMM was shipped and I received a ...
10
votes
2answers
370 views

Why are my VGA vram to vram copies so slow?

I'm doing some mode x programming and I noticed that my vram to vram copies are much slower than I expected. My copying method was described by Michael Abrash in his Graphics Programming Black Book ...
13
votes
2answers
1k views

What is a use case for the JAM instruction on the MOS Technology 650x family of processors?

I was reading about undocumented opcodes for the 650x family of processors and discovered JAM, an instruction "which simply causes the CPU to freeze, requiring a hardware reset or power cycle to ...
23
votes
4answers
2k views

Use of undocumented opcodes

I figure this is fitting for Retrocomputing.SE because CPUs like the 6502 and Z80 and the PDP-8, and probably others, have undocumented instructions and will happily execute them, in contrast with ...
3
votes
5answers
263 views

How to teach the Z80 to count milliseconds and microseconds like Arduino?

I make a homebrew (for hobby) game console on Z80A, and I need help. Now I'm stuck - I need to be able to count milliseconds and microseconds in the code. For example, how it is done in Arduino : ...
2
votes
1answer
108 views

How to load into FAST RAM on Apple IIgs?

The Apple IIgs (last, ROM03 version) came with 128K of standard RAM and 1M of FAST RAM. The distinguishing characteristic of the FAST RAM is that code running from there can run at 2.8 MHz instead of ...
2
votes
1answer
110 views

PlayStation 2 Slim with analog A/V output having noise interference issues

I'm having an odd issue with the aforementioned system, the A/V receiver is a RCA STAV-4180 unit, and being from 1996, it's still a great unit. So far, while it's tape output for recording does have ...
52
votes
5answers
10k views

Which Linux or BSD distributions do still support i386, i486 or i586 CPUs?

Unfortunately Debian kicked out Pentium 1 (i586) CPU support from its 32-bit PC port (named i386 for historic circumstances) for its next stable release Debian 9 Stretch. (Then again they complain ...
7
votes
1answer
727 views

What is this Amiga 2000 mod?

I got an Amiga 2000, board Rev. 6 Does anyone know what is is? (click to enlarge)
2
votes
1answer
213 views

Historical speed of linear programming solvers

A few years ago, I remember seeing a video of Ray Kurzweil discussing how linear programming was an example of how software (algorithms) - independent of hardware - is also getting faster (...
24
votes
3answers
5k 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 ...
1
vote
1answer
80 views

Reserving extra directory blocks with cpmtools?

I'm trying to create a boot disk for the Kaypro II (from scratch). I've been using cpmtools to generate file system images for other platforms, mostly with success. However, the Kaypro II has this ...
7
votes
2answers
3k views

Was the IBM 5100 ever used for codebreaking?

There's a rumor that there's something embedded in the IBM 5100 which makes it useful for codebreaking. What is the legitimacy of that claim?
-1
votes
0answers
210 views

Program-files/data-files in RAM on retrocomputers? [closed]

Question/Questions How many program-files could be in RAM at one time ( See the update below )? How many data-files could be in RAM at one time ? Was it possible to 'somehow' set a data-file as ...
4
votes
3answers
149 views

How did console flexowriters connect to their computers?

Several early computers (e.g., KDF9, LGP30) used Friden Flexowriters for console functions. What was the nature of the connection between the Flexowriter and the computer? Was this something we ...
0
votes
3answers
297 views

The earliest a home-computer or home-robot could be interfaced with a commercially available camera?

What was the earliest date a home-computer or home-robot could be interfaced with a commercially available tv-camera or digital-camera . Although I'm asking this question for the purpose of computer-...
2
votes
1answer
96 views

SGI Octane and Octane 2 fail to boot

(Following up from Monitor for an SGI Octane?) I booted both my Octane and Octane 2 machines for the first time. I have a monitor connected via a 13W3-to-VGA adapter, but no PS2 keyboard or mouse yet....
9
votes
5answers
1k views

Largest practical motherboard for early computers

The power of a computer is often effectively determined by the size the RAM can be expanded to. In many cases, this was even more important than CPU speed: Memory-limited workloads In the early days, ...
7
votes
3answers
347 views

Why did scandisk exist?

As far as I can tell, chkdsk as been part of DOS and Windows since day one. However, in later versions of DOS, chkdsk was shipped along side scandisk. As of Windows 98, running chkdsk will result in ...
2
votes
0answers
138 views

Would anyone have made a mechanical, or electronic camera for their computer or robot? [duplicate]

Would anyone have made a mechanical, or electronic camera for their computer or robot ? Parameters Of The Question As a home-project [ Although, any example of a mechanical-tv-camera or mechanical-...
17
votes
2answers
2k views

Why does this BASIC program declare variables for the numbers 0 to 4?

On pages 150 to 154 of William Tang's (1982) Spectrum Machine Language for the Absolute Beginner, there are these lines of code. (Note GOTO 9000 is the first non-REM statement in the program). 9000 ...
11
votes
1answer
458 views

What is this Amiga 1200 mod?

I got an Amiga 1200 off ebay and it works great, board looks perfect, no leakage, no bad traces, nothing, and yet I have this mysterious mod I've never seen before. Does anyone know what it is?
10
votes
3answers
791 views

Did Apple bundle a specific monitor with the Apple II+ for schools?

Sometime in 1980 (or maybe 1981) my school district purchased its first batch of Apple II+ computers. I remember vividly they had absolutely no idea what to do with them, and so the machines were ...
2
votes
1answer
101 views

ISVs in the mainframe and minicomputer eras

In the eighties, there was a vast flowering of small independent software companies. Business and productivity software for the IBM PC, all manner of novelties for the Macintosh, games for the ...
6
votes
2answers
485 views

Did any Apple II games use a “timing resistor”?

A science-lab program for the Apple II (I forget the name) had a board that plugged into the joystick port and included a "timing resistor". While I don't know what the program actually did with the ...
4
votes
2answers
264 views

Desk computer with embedded CRT, 8" floppy

Back in 1981, my high school's computer classes were something like Computer Programming I and II, which taught BASIC on the Apple ][+, and a Computer Programming III class. In the III class, a ...
2
votes
3answers
235 views

What are some notable historic keyboard designs with unusual colours? [closed]

I remember that many older computer or terminal keyboards were quite colorful, and apart from grey and white, often featured some orange, red, green or blue keys. I have seen some in computing centers ...
50
votes
6answers
10k views

How did old MS-DOS games utilize various graphic cards?

Nowadays each graphic card has some driver in operating system that translates some (typically) standard API such as OpenGL, so that programmers use some standardized API code to tell graphics cards ...
1
vote
2answers
265 views

Old grid-based puzzle game with snakes that wake up when on the same row/column as you

I'm trying to find an old game: Played on an old computer, not sure which kind. (early/late 1990s?) Graphics were grid-based and "8-bit-seeming". Locations included plains and caves. Movement was ...
12
votes
1answer
806 views

Why the DOS extender and DPMI were unavailable to DOS programs on 286 standard mode of Windows 3.0

An old article on Windows 3.0 from PC Magazine (June 11, 1991, page 348) said that: Using standard mode, the Windows DOS extender and DOS Protected Mode Interface (DPMI) are available to Windows ...
0
votes
3answers
638 views

Was Hurd kernel created as a modification of Linux kernel?

As I know, shortly after Linus Torvalds liberated the Linux kernel it was implemented in GNU operating system which is since then known as GNU/Linux or GNU+Linux. From the GNU article in Wikipedia I ...
4
votes
3answers
233 views

Can someone explain this algorithm used to compute the auxiliary carry flag?

I'm debugging my 8080 emulator and I've gone the route of comparing it to the output of another tested emulator to see where I went wrong. When calculating the auxiliary carry flag, I used this ...
2
votes
1answer
120 views

Pac-Man-like: Playing a Excavator bucket or mining drill on a cable

I remember playing this game on the C=64 in the late 80s or so. It was 2d 'platformer' arcade game where you have to clean the screen from pills like Pac-Man, but in a different way. You would always ...
2
votes
3answers
164 views

Paging vs. segments in the Z8000

Having post-dated either, I came to understand the difference between paging and segmentation to be that the former refers to fixed blocks while the later can point anywhere. To do so, the segments ...
5
votes
1answer
179 views

What was the reasons for DEC engineers to choose MMU page size in VAXen?

MMU page size in VAXen is just 512 bytes. Such a small size causes increased number of MMU page walks and leads to TLB thrashing more often. Current tendency is to have MMU pages as big as 2 Mbytes. ...

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