All Questions

0
votes
0answers
67 views

What is this tool that was once used to teach beginner level BASIC?

In the early 1980's there was a small handheld device that looked like a calculator. It was a tool to teach beginner level programming in BASIC. Its ad slogan was "keep it near you". I never had one ...
1
vote
2answers
89 views

Why did the Apple //e behave in certain unfriendly ways?

When I began high school in 1987 all the computers in the lab were Apple //e desktop computers. So I have a question that has haunted me: The disks were floppy disks, often the Verbatim brand, to ...
8
votes
2answers
498 views

Why wasn't EBCDIC designed with contiguous alphanumeric characters?

Inspired by this question on ASCII, I have wondered similar things about EBCDIC. At work we have an EBCDIC file that gets sent to a mainframe (I presume an IBM one) and to view it on my laptop I ...
1
vote
1answer
101 views

Integer overflows in MS BASIC

I only recently learned that the early MS BASICs had integer variables and do not have a machine that runs it. So perhaps someone with a PET or C64 could answer these questions? For one, were there ...
5
votes
2answers
188 views

How did Satoru Iwata compress Pokemon GS to fit two regions on a single cartridge?

Satoru Iwata's story of saving the development of Pokemon Gold & Silver by compressing its assets to fit on the GameBoy Color cartridge is something of a legend. Iwata optimised the game so much ...
32
votes
4answers
5k views

Why wasn't ASCII designed with a contiguous alphanumeric character order?

Anyone who has dealt with strings at a low level (e.g., writing a parser in C), knows that doing so tends to involve frequent checks of—either manually, or through isalpha(), isalnum(), etc—whether a ...
8
votes
6answers
1k views

Single level file directory

Have there actually been any commercial operating systems with a single-level, limited capacity file directory? I remember vaguely that the early versions of MS-DOS FAT12 may have had a single layer, ...
2
votes
1answer
153 views

Extracting files from a Windows 3.1 (16bit) install/archive (game)

I'm interested in doing some practice work around legacy systems out of pure recreation. I want to extract data or information related to a DOS game running on the 16bit arch of Windows 3.1 (1991 ...
2
votes
1answer
106 views

Horizontal hold on Atari 800xl connected to flat screen tv

I recently picked up an Atari 800xl from ebay that seems really solid and I am using a DIN to RCA cable through an AV to HDMI adapter to connect it to my flat screen tv. This all seems to work except ...
9
votes
0answers
324 views

How good was Woz's FP code?

I just came across this amazing 1976 article by Woz. In it he describes a relatively complete floating-point system for the 6502 with a 32-bit format (similar to earlier MS code). I understand the ...
6
votes
2answers
408 views

Can Access Fault Exceptions of the MC68040 caused by internal access faults occur in normal situations?

Note: I only have the MC68040 USER'S MANUAL at hand. In chapter 8.2.1 "Access Fault Exceptions", it is stated that those exceptions can be caused by Bus Error or Internal Access Faults and by that ...
3
votes
1answer
96 views

how can I connect a scanner with Centronics 50 output to USB?

How can I connect a Legacy scanner with a Centronics 50 output to a laptop with USB ?
21
votes
2answers
2k views

Details of video memory access arbitration in Space Invaders

I am working on an FPGA implementation of the original Space Invaders arcade machine and I'd like to implement access arbitration between the CPU and the video system. I can imagine several ways of ...
9
votes
1answer
2k views

A way to connect Microsoft Green-Eyed mouse to modern computer?

Is there a way to connect the 1983 Microsoft "Green-eyed" mouse to a modern PC or preferably Mac (running Windows on virtual machine)?
2
votes
1answer
68 views

CompactFlash driver for Sony Clié (Palm OS)

A Sony Clié (PEG-NX70V) has come into my possession. It runs Palm OS 5.0, and has both a MemoryStick slot and a CompactFlash slot. The latter is only designed for use with a WiFi card, as Sony ...
1
vote
1answer
69 views

Atari 1040STFM PSU Hissing, high pitch sound when on

I have an Atari, which is working correctly, but the power supply makes this hissing noise as soon as it is turned on. What may cause it?
3
votes
1answer
81 views

MASS MicroSystems MO/128 Magneto-Optic Drive mystery

I found this drive in one of Atari lots. Apart from few mentions in old articles I can't find any info whatsoever. Can you help please?
6
votes
1answer
250 views

AT system without -5v

I have recently built a 80386 system. Lacking any AT PSU I connected a PicoPSU using an ATX->AT power adapter. Only card connected was a gpu (Trident TVGA 9000i). System performed BIOS checkup ...
0
votes
1answer
98 views

What type of video card would be able to drive a VGA monitor that uses a standard HD 15 pin connector with a non VGA standard pinout?

I was browsing old FAQs on the wayback machine(1) and noticed that it said some early Mitsubishi Diamond Scan monitors, and reportedly the Dell Ultrascan 17ES monitor(2), use a standard HD DE-15 VGA ...
3
votes
3answers
157 views

Is there any tool to convert .DSK to mp3 file?

I was looking into the Apple II disk server (See below for background information) and curious if there is a tool that can actually convert .DSK image to .MP3 file, as the underlying c2t only supports ...
0
votes
0answers
79 views

I cannot delete files on IRIX 6.2

I started using IRIX 6.2 so I could do some Nintendo 64 Development for the IRIX community. WARNING: IT IS A VERY WEIRD SITUATION! Also, I am using root. The file manager GUI states that the files ...
-1
votes
0answers
75 views

DEC PDP-11 Boards [on hold]

PDP-11 BOARDS The following boards are all Digital, except where stated. There is one board except where stated. All boards came off working systems but I can’t guarantee they are still working! I ...
4
votes
0answers
165 views

Did any mechanical computers or calculators handle divide by zero with an exception, or did they all loop?

I just saw this video of a mechanical calculator dividing by zero. Did any mechanical calculators or computers ever provide for a failure mode on divide by zero? Or did they always handle it by ...
1
vote
1answer
110 views

What capacitors to use in Atari 1040STE power supply

I'm working on Atari STe, which has dodgy caps on PSU board. 2 of them are in desperate need for replacement. Can anyone suggest quality brand to extend the life as much as possible?
20
votes
5answers
5k views

How well known and how commonly used was Huffman coding in 1979?

Infocom's Z-Machine, designed in 1979, compresses text using a basic 5 bit code which is not very efficient in practice, achieving maybe a 1.5:1 compression ratio. Huffman coding would be far more ...
2
votes
2answers
166 views

What was the format for .OBJ files produced by M80.COM for CP/M?

When DOS released in 1981, the assembler that came with it produced .OBJ files that were OMF format. However there was a predecessor to it, M80.COM that ran under CP/M and also used .OBJ as the file ...
16
votes
2answers
3k views

Why did pressing the joystick button spit out keypresses?

If you pressed one of the joystick buttons on the TRS-80 Color Computer while running BASIC, it would act as if @ABCDEFG were typed. Pressing the other joystick button would similarly type out ...
8
votes
1answer
205 views

Anyone have more information on the “Hammerstein TV Games” 1st gen console?

I have what appears to be an early games console (supported games are variations on the theme of "pong", or ball and paddle games) manufactured in South Africa. Does anyone have more information or ...
5
votes
2answers
140 views

What combinations of modifier keys can you detect on an Apple II?

Apple II computers other than the IIgs (which uses ADB) have a hardwired keyboard combined with the paddle/joystick ports for input. What combinations of modifier keys can you detect? I know that the ...
1
vote
2answers
193 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 ...
9
votes
2answers
849 views

Is there any difference between Т34ВМ1 and КМ1858ВМ1/3?

In the Soviet Union, Z80 compatibles were manufactured under at least the following designations: Т34ВМ1 КМ1858ВМ1 КР1858ВМ3 At least some of these were manufactured from the U880 masks that were ...
6
votes
1answer
1k views

What was the first third-party commercial application for MS-DOS?

What was the first third-party commercial application for MS-DOS intended for IBM PC-compatible computers?
13
votes
1answer
5k views

What is the oldest commercial MS-DOS program that can run on modern versions of Windows without third-party software?

What is the oldest commercial MS-DOS program that can run on modern versions of Windows (such as Windows 8.1 or Windows 10) without third-party emulators?
6
votes
1answer
303 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,...
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 ...
6
votes
5answers
247 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 ...
1
vote
2answers
184 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 ...
4
votes
4answers
982 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 ...
2
votes
1answer
113 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 ...
2
votes
1answer
119 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 ...
8
votes
3answers
365 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 ...
3
votes
5answers
297 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 : ...
7
votes
1answer
753 views

What is this Amiga 2000 mod?

I got an Amiga 2000, board Rev. 6 Does anyone know what is is? (click to enlarge)
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 ...
2
votes
1answer
121 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 ...
1
vote
1answer
86 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 ...
10
votes
2answers
393 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 ...
2
votes
1answer
104 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....
11
votes
1answer
471 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?
2
votes
1answer
107 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 ...

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