All Questions

I remember finding out there was a secret area in both games that you could only get to if you were playing on a Game Boy Advance. Even the 3DS releases don't allow access to them. My question is, how ...

My very rough understanding of character encoding history as it relates to the Unix family of platforms/languages is that: They started using single-byte (7/8/9-ish bit) character sets like ASCII/...

I remember being captivated as a teenager by an issue of Popular Mechanics that introduced the BASIC programming language. It would have been late 70's or early 80's. Anyone know how to find which ...

I've looked at a few different websites and they all agree that a JP nnnn instruction (where nnnn is a 16-bit address) always takes 10 states to execute. According to what I've read, all of the ...

I have two old Nokia phones and I'm trying to export all the SMS messages stored in them to my laptop. The first one is a Nokia-3110c. I managed to connect it to my laptop using a USB cable and ...

The Rockwell R65C00/21 and R65C29 are described in an October 1984 datasheet ("R65C00/21 dual CMOS microcomputer and R65C29 dual CMOS microprocessor," Document no. 29651N64, rev. 2) which is ...

Unlike a normal Z80, the Game Boy has no CALL pe/po, JP pe/po or RET pe/po instructions. I've been trying to figure out how to detect integer overflow on the Game Boy. (It doesn't have those ...

I'm in the process of restoring an old Compaq LTE Elite 4/75 laptop, which was missing its hard drive, so I thought I'd try booting using an SD-to-IDE adapter. On my main workstation I created an ...

Before asking this, I read the Wikipedia article. I've been confused about this for many, many years. I'd like to finally get it straightened out. What exactly is the difference between "RGB"...

I posted this in video production as well, but it's really more of an obscure serial thing: I have a modern SSD video recorder deck that inexplicably can only be remote controlled by RS-422 (Atomos ...

Even in the last version of the DOOM engine, v1.9, used for Final DOOM, there is this strange limitation in which all the monsters have an invisible, infinitely tall "pillar" above and ...

Why use a JWT Refresh Token. At https://www.oauth.com/oauth2-servers/access-tokens/refreshing-access-tokens/ to use refresh token, i need to send: POST / oauth / HTTP / 1.1 token Host: authorization-...

The following video for Kraftwerk's Die Roboter is very interesting because it features some effects which I think might require a framebuffer to achieve. Having a framebuffer in 1978 would to my ...

I was looking through the Super Star Trek code when I noticed this for the first time: 7540 REM INPUT"DO YOU WANT A HARDCOPY? IS THE TTY ON (Y/N)";A$ 7542 REM IFA$="Y"THENPOKE1229,...

Currently I'm digging in the history of computer graphics and found the Windows default 20-color palette. It's based on the Windows and IBM OS/2 default 16-color palette but has the four additional ...

I saw a tweet today about what it claims is "the tallest PC case" which appears to have been made by SuperMicro: Further tweets in the thread include pictures of the inside of the case, ...

I know I can use LOAD "PROGRAM",8,1 to load a program in a certain spot in memory, using the first two bytes of the file on disk. Now let's say I have used the .MON command on the Final ...

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 ...

The IVT is at 0x0000-0x03ff while the BDA is at 0x0400-0x04ff but boot sectors are loaded at 0x7c00. What was at 0x0500-0x7bff that caused this convention? I'm also curious why some MBRs relocate ...

Unless I'm reading the manual incorrectly, the following should produce $11 when D404 = $10 (I'm turning on the gate for voice1 which has been previously set to triangle wave %00010000/$10) 00153 ...

So I was porting one of the old BASIC games from the book "BASIC Computer Games", Ref: https://github.com/coding-horror/basic-computer-games to Python, just for fun. I came across the ...

This is a grab from a 1988 movie called Vampire's Kiss. It has twin disk drives (5.25" from the looks) and what looks like a built-in printer?

Years ago (circa 1996-1997 maybe?) I ran a MS-DOS program that showed a map of the whole earth, updated once a minute with the time, timezones, and light/dark areas of the planet, taking up the whole ...

I've been trying to implement a blitter in MS-DOS, but before I do that I wanted to test the various graphics modes of the VGA graphics card. (I'm emulating using DOSBox.) According to this paper on ...

I came across an Intellivision in a box of stuff. When I looked it up on Wikipedia, it said that it uses a CP1600 that is based off a PDP-11. There's a weird entry on the wiki page: CP1600 did not ...

In this answer to 'Why were TECO variables called Q-registers?' I reference documentation indicating that the original Q-registers were separate from the same-named G-registers. (I.e., X1 would store ...

Where can I find a Windows 3.11 driver for a Creative Technologies CT6042 Video Blaster card? I need it to recover a piece of 90s era test equipment.

STC MOV AL, 5 SBB AL, 3 ; AL = 5 - 3 = 2, but I am getting 1 .. why? RET

Empirically, I've found that this routine (i8080) divides value from E by B and returns the result in D and E (result and remainder of division). divide_by_12_with_rest: MVI C, 9 ; @1 MOV A, D ; @...

I'm trying to define a section of data in a program. The Apple 6502 Assembler/Editor mentions an assembler directive called "DSECT" but I can't tell if I'm using it correctly or not. Here is ...

In a parser library I am maintaining, I stopped recognizing singular Carriage Return characters as line endings to reduce complexity in the tokenizer's position tracking code, a perennial source of ...

In the late 80's, I had an interesting incident with an Atari ST that I've never really understood. I was using some graphics software that I recall was very similar to the way Microsoft's Paint still ...

Dartmouth BASIC seems to have gotten strings around 1968, and BASIC uses the $ on variable names to indicate that they're strings. This is a strategy for avoiding the need for explicit type ...

Many early compilers and interpreters had maximum length for variable and function names. Usually you could use longer names but everything beyond e.g. the first 8 characters was discarded. This ...

The BASIC I'm most familiar with is Atari BASIC since I had an Atari 800 way back when. The Atari BASIC Source Book includes details about how Atari BASIC maintains variables. There is a Variable Name ...

The IPv4 specification requires that IPv4 devices must be able to reassemble a datagram with a length of a minimum of 576 bytes. Looking back into the creation of the Internet... RFC 791 in defining ...

This is driving me nuts. I am certain I have a downloaded scan of the source code to the 6502 ML monitor Woz wrote, but pre-dating Apple's use of the monitor. I even remember there was some text ...

In the early days of compilers, it was expected that programs would generally be stored in an inexpensive medium (such as punched cards or magnetic tape) when not in use. Although it was possible to ...

Background In two's complement arithmetics, if one wants to calculate a subtraction having only an adder that calculates {cout,result}=full_adder(arg1,arg2,cin), where cin and cout are incoming and ...

In recent years there has been a push by some to move away from using the term "master" in source code management systems, often by renaming the "master" branch to a "main&...

The 6502, like many 8-bit processors, has a somewhat arcane opcode-mode restrictions. On most such processors, the restriction is a clear result of trying to pack a lot of instructions into a limited ...

How often was C used to program firmware for 8-bit processors in the early 80s? I'm reverse engineering a firmware binary for a device built around a Hitachi 6303 processor, manufactured in 1983. Even ...

I came across this little machine in a roundabout fashion - 4kW of RAM and 1usec cycle for "under $10,000"! (not including ASR33) It seems this is largely lost to history. Does anyone know ...

I have a Commodore PC 30-III but I can't find a way to start the BIOS menu. It displays the following message during startup:

I've been doing a lot of reading about the ways Apple IIc owners expanded their machines in the absence of the IIe's slots, and it's very intriguing stuff. The ones that I'm most curious about are the ...

If not the first, then the one that became popular first (in any application; this is not limited to aviation systems). A control display unit, CDU for short, is fairly common in aviation, perhaps ...

I have Commodore PC 30-III 286 machine with a serial port at the back labelled "mouse". If I plug my Commodore mouse 1900 serial mouse then execute mouse.com at the DOS prompt then I get the ...

TL;DR Following on from OmarL's comment, to the closed question, Why did the Spectrum Next choose Z80 on FPGA?: But also, the eZ80 is not compatible with the ZX Spectrum because it uses port FE for ...

In order to help people who want to integration-test tools which shell out to The Unarchiver's lsar and unar utilities, I'm trying to build a legally clean repository of test archives in StuffIt SIT ...

How do you clean keyboards with buckling springs? I have mentioned in an earlier question that I've recently bought an IBM keyboard but how do you clean a keyboard with buckling springs? I only know ...