All Questions

The docs for Ultimate-II+ expansion cartridge for the Commodore 64 state: It is able to read D64 files, as well as D71 and D81 files (no partitions), T64 files. So what are D64, T64, D71 and D81 ...

I find information and resources about connecting 18-12 years old devices to Internet, specially PDAs and phones. I am also interested in computers but they will have less limitations and issues, as ...

There is a well known war in computer science that involves a lot of its domains: The Protocol War (https://en.wikipedia.org/wiki/Protocol_Wars). I would like to know, what was the reason companies ...

The 8-bit Apple II had two disk operating systems with different disk access semantics. DOS used tracks and sectors. A sector is 256 bytes. ProDOS used blocks. A block is 512 bytes. But mapping ...

I'm interested in working with the most common Apple II disk image file format, .dsk. (I only programmed these machines briefly in Basic around 1979-81 and have not been in the emulator scene, so I'm ...

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 ...

The photo below shows what may be a CRT for the TX-0 (transistorized experimental computer) in 1956, referring to what may be a CRT on the left side, not to the CRT on the right side . If that is a ...

Does anyone know if the Mega Drive or Arcade version of Afterburner use FM synthesis or sound samples for orchestra hit in its song "Afterburner". I find oscilloscope views of each version but I'm not ...

Is the model shown on pictures an authentic Commodore C386SX-LT? Why does it look different to other photos on the Internet (some additional grey keys? above keyboard): http://www.spacereh.de/hc/com/...

I found my assumed long lost “win98” toshiba protege laptop in our wet and moldy storage container. Was there for years, through cold-humid variances. The files on his computer are extremely ...

I recently picked up a 1541 Ultimate II+ for my Commodore 64 and have been amazed at how this device seemingly can do every flash memory and other enhancement feature for the machine, short of CPU ...

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 ...

/CMD files on the various TRS-80 Model I and III OSes are machine code command files. They seem to have some internal format but not really a file header. They often start with 01 02 and then a 16-...

I got a control pedal from an old sewing machine that connects to a 3.5mm jack. It fits in the audio/microphone jack of my laptop. Is there any way that I could detect from the laptop this pedal ...

I just picked-up a Macintosh Color Classic with an Apple IIe card. I've never used one of these before but was able to get it to enter into Apple IIe mode. However, I cannot seem to figure out how to ...

I have used Windows 98, and observed that its shutdown is very fast. How is that?

In my reading to try to learn about the disk layout, directory, and boot process of TRS-80 Model I and Model III, I see some unusual words come up again and again. Along with the common terms "track" ...

I found Why do C to Z80 compilers produce poor code? very interesting as it pointed out that C (which was designed to be an abstraction of a CPU for porting Unix) was not a very easy language to ...

VICE needs a file called dos1541 if you want hardware emulation of the 1541 disk drive. What does that file contain, exactly? The 1541 seems to have two ROMs: a DOS and a KERNAL. But if I take the ...

I can find enough mentions of bootable disks for TRS-80 Model I and Model III to be confident that they could boot from disk, but so far I'm failing to find much info on how that worked. In ...

The original Apple IIc had a 27128 16 KB ROM mapped into the $C100-$FFFF range (the $C000 page was decoded for I/O). According to the Apple IIc Technical Reference Manual the ROMEN1* and ROMEN2* ...

I've decided to add support for some more classic Z80 computers I used to use to my Ghidra modules, and the first Z80 systems I used were the TRS-80 model I and model III. I've found documentation ...

I have installed Microsoft C 5.10 on DOS 6.22. It created a 'LIB' directory with static libraries to link against. Now I need to extract the symbols and the code for the functions from them, but can't ...

I'm just curious why the 8086 seems to be lacking in an adjust opcode for fixing up packed BCD multiplication. It seems like it would be a useful thing, and packed BCD seems to be more common to begin ...

What is exact meaning Windows NT 3.51 title bar buttons? Arrow up is maximize and arrow down minimize? And left button is close? Its my assumption right?

I'm trying to figure out how the Auxiliary Carry flag on the 8080 is affected by logical instructions. Reading the Intel 8080 manual, it seems that logical instructions do not affect AC: The ...

How can I find where in memory to locate the current Basic program in an Amstrad CPC/PCW family Zilog Z80-based microcomputer? Is it always the same address? A different well-known address depending ...

The native floppy disk format/layout or "filesystem" used by Amstrad microcomputers such as the CPC and PCW range and by the Sinclair Spectrum +3 are versions of one that came from CP/M. In Amstrad ...

Short story I am curios about when file based communication / design patterns became obsolete in enterprise applications. Although I have been programming for more than 15 years at enterprise level, ...

Let's say you have a hypothetical 8-bit processing machine with 256 bytes of memory. You want to load the value stored in memory location $f2 into a register. However, with a data bus of just 8 bits, ...

I bought an LC 475 for parts and repair on ebay. When it arrived it seemed to work okay but the video was all stripey. After some diagnosing I spotted a rotten trace near the the VRAM simms. I ...

It's look like very old thing to me: It's in Black and White display. As you can see, it has a socket on the top of it . What's the name and model of this computer monitor?

I have a working (I think) Amiga 500 system with an internal DF0 drive and an external DF1 drive. The Amiga 500 powers up with Workbench v1.3. Can anyone tell me how to access a game disc (Marble ...

I'm trying to install a 68060 accelerator on an Amiga 3000T, but I cannot figure out the correct jumper settings. The information I've found online is: J100 CLK90 Delay jumper. This Jumper has three ...

I recently added support for .scl images files to my Ghidra module which already supported .trd images. They are both representations of TR-DOS floppy disks as used mainly on Spectrum clones from ...

I'm curious to understand why the Spectrum Next uses Z80 on an FPGA instead of something like at eZ80? I would have imagined they would choose the eZ80 since it is still a production part. Anyone ...

I am curious to learn about any developments in computer theory, hardware, and software that took place outside of the United States, in the middle of last century (~1940s-1980s). I have read 'Where ...

From what I've read, the first FORTRAN compiler built a machine-code program entirely in memory; it was, in fact, designed to read the entire source code of the program, and then sequentially load ...

If I had a hypothetical computer just like nowaday's computers, but it had an NMOS 6502, would it provide me with a better emulation experience than if I were to emulate the 6502 inside software? Also,...

The 6502 uses the carry bit system (over a borrow bit). On such machines, the bitwise NOT is applied to the subtrahend before it is "subtracted" (really, added, taking advantage of two's complement) ...

I'm wondering if it is possible to buy an sort of device currently in production that uses a z80 compatible CPU - not an FPGA. I don't want to build a kit or use a soldering iron. I'm also looking ...

A preprocessor is a tool that takes source code as input and outputs a modified version of it for input to a downstream tool, such as a compiler or interpreter. Preprocessors can be used to implement ...

There's a glitch in the original Super Mario Bros., that causes Mario to become an unused sprite(Small Fire-Mario). I'm unsure how the glitch works, but I'll show the instructions on how to pull it ...

When installing Windows 98, the part of the setup process where you enter things like product details looks... different. The scrollbars, buttons, title bar and such look more like they belong in ...

In an answer about screen formats Raffzahn wrote: "In 1920 the Tabulating Machine Company (originally The Hollerith Electric Tabulating System, now part of CTR Holding) introduced a new printer-...

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?

I just picked up a used Apple IIc. For some reason all I get when I boot is Check Disk Drive on the screen, even with a bootable disk in the internal drive: I cannot even get the system to read the ...

I purchased a vintage Apple IIc computer and I want to make sure there are no failing components. I booted up the computer while pressing both Apple keys (open and close) at the same time. The ...

Back in the 1980s-90s, using a UNIX system required running expensive servers or paying for timesharing service, so they were beyond the reach of most individuals, and only available to members in ...

The 80486 processor can execute many instructions in a single cycle, such as a register-to-register add instruction (ADD EAX, EBX, for example), which one would generally assume is fairly complex, ...