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10
votes
1answer
884 views

Why is the 'echo' command called 'echo'?

This is an essentially trivial question, but anyway: several operating systems have a command to display a specified text string on the terminal, or standard out, or whatever (depends on system to ...
5
votes
2answers
552 views

How can I ensure my computer design is not anachronistic?

I have a strange desire to make an imaginary competitor to the Atari 800 (6502 + different custom chips). As far as I can see people are mostly interested in making "my childhood computer, but with ...
4
votes
2answers
270 views

Commodore monitor to VGA or HDMI

I have this monitor, which I think is a Commodore 64 monitor. I would like to connect it to a pc. Anyone know how to convert VGA or HDMI to this connector format? I've tried searching, but so far I'...
19
votes
1answer
877 views

MOS 8502, just a 6510B?

I'm looking over what little I can find on the 8502, and from what I can see it appears to be a 2 MHz version of the 6510 with an extra I/O pin. Much ado about the speed, but the Atari's 6502B's were ...
12
votes
1answer
1k views

What manages Upper Memory Blocks (UMBs) in MS-DOS?

I had always assumed that EMM386.EXE was responsible for managing the Upper Memory Blocks - UMBs - the memory space between 640KiB and 1MiB in real mode x86. For example, on MS-DOS 6.22, help emm386....
0
votes
1answer
262 views

Which retro personal computers, if any, can use a modern day monitor? [closed]

I play around with emulators, and would love to go back to my roots, with physical ZX81, BBC Micro, Amiga, etc. Unfortunately, those all require a TV as output. I suppose that I could buy a cheap one ...
4
votes
1answer
241 views

Can the Nintendo 64 run code directly from ROM?

I've read that the usual way to execute code on the N64 is to use DMA to copy it from ROM into RAM, and then run from RAM. However, it seems that the contents of the ROM are directly visible to the ...
10
votes
3answers
2k views

Disable memory refresh on Z80

Is there a software method of disabling memory refresh on the Z80? Or would it be acceptable to create a hardware method of disabling the address bus during the refresh cycle? If I switch off the ...
3
votes
0answers
278 views

What is the cause of Trent's circuit board strategy? [closed]

For those of you who are unaware, professional speedrunner Trent Hall discovered a now banned strategy in Goldeneye 007. This strategy (called Trent's Circuit Board Strategy) consisted of plugging a ...
9
votes
1answer
2k views

Sources for some old BASIC games

Poking about in early issues of Dr Dobbs' Journal (the journal of the People's Computer Company, or PCC) I came across a listing for BASIC games available on tape. Many of these are widespread, but a ...
0
votes
2answers
112 views

ASCII ASA X3.4-1963 and Finite State Machines?

I'm reviewing the historical original ASCII standard. There are many control characters. Does anyone know the history of them and where finite state machines that made use of them may be documented? ...
7
votes
2answers
5k views

What was the point of the label on the bottom of the NES? [closed]

The original NES has a label printed onto it that the device would not "cause harmful interference". Why would they write that? Did people think the NES might be dangerous? Is this some kind of legal ...
2
votes
2answers
217 views

Is there such thing as para-emulation? [closed]

Is there such thing as a para-emulation? Like para-virtualization but for emulation? If so, where could I find a website that describes it?
16
votes
4answers
2k views

80286 real mode emulator for 8086

While trying to use a "modern" sound card (an Aztech Sound Galaxy Pro 16 II) in an XT compatible 8086 computer, I encountered the problem that the drivers and tools (like the mixer initialization tool ...
1
vote
1answer
224 views

Estimating contents of old printed circuit boards

I am sorry, if this is not a good place to ask, but is there any general rule of thumb about how much precious metals could you expect to get out from 197x(?) printed circuit boards, especially Soviet ...
3
votes
1answer
393 views

Why do parallel universes exist in Super Mario 64?

For those of you who are unfamiliar, Super Mario 64 is an extremely competitive speed game, and because glitches are allowed on most major leaderboards, many very talented glitch hunters have torn the ...
38
votes
1answer
3k views

Z80 CPU address lines not stable

I just got a Z84C0020PEC and wired it up to test it, using this circuit: Except that I've added LEDs to A0 through A9. It appears that A0 through A6 operate correctly, but A7 though A9 (I've not ...
6
votes
2answers
289 views

what is DMA and how does it work?

I've heard the term 'DMA' being used a lot in reference to older consoles. My very basic understanding is that it's a way for the console to access memory directly. But directly as apposed to what? ...
5
votes
3answers
394 views

How to use HGR2 (or HGR) on an Apple II

I am a big fan of the TV show lost, and I was trying to make the Dharma Initiative logo. But at certain point I couldn't add new lines of code and the final part of the logo was cut off. I tried to ...
12
votes
1answer
743 views

The behavior of the auxiliary carry flag in subtraction on Intel 8080

Does SUB B on Intel 8080 set the auxiliary carry flag when the accumulator and the B register are 1 and 0, respectively? On Z80, which was designed to be a backward-compatible, albeit not fully, ...
3
votes
1answer
193 views

Adding control characters to string constants in ca65 assembler

According to the cc65 documentation, a string constant in assembler programs can be defined with the .ASCIIZ command. However, I could not manage to sneak control commands in, for example, the ...
3
votes
0answers
138 views

How are the index registers on the Censor 932 accessed?

The Censor 932 CPU architecture has one instruction type that takes a 3-bit "index register" field, but looking at the rest of the instruction set, I can't see any instructions that read, write, or ...
25
votes
2answers
7k views

How does the Gameboy Link Cable work?

I've been looking into implementing Gameboy Link Cable compatibility into Bizhawk (which does not support it yet) using Lua. The problem is that I can't find any mention of how it works online. I ...
5
votes
1answer
165 views

Different handling of ASCII interpretation between ca65 and cl65

I stumbled upon a divergence in the ASCII upper case/lower case handling when using assembler and linker of the cc65 suite separately (I used cc65 V2.15 on Win10). For a test I made the following ...
4
votes
1answer
129 views

How to test a chat script with a uucp linux and uucp(server) unix?

I like to play with old networks, uucp is really and advanced(is from the 1978) for that time. I have setup a uucp server in a tru64 unix server. On tru64 server I have edit /etc/inetd.conf uucp ...
11
votes
0answers
208 views

Unix on the H11?

I'm curious if anyone is aware of actual uses of Unix on the Heathkit H11? I don't see any technical reason a memory-expanded H11 couldn't run Unix, but can't find any examples of it doing so.
37
votes
3answers
5k views

What happened to the SEV instruction on the 6502?

The 6502 has a group of opcodes which copy bit 5 from the opcode into one of the status flags. (I know it's not implemented this way, but it looks as though the bit fields are: 2 bits to select the ...
0
votes
0answers
264 views

Old Computer Game about a robot and questions

I'm trying to remember an old game I used to play as a kid. It may have been a commodore 64 game, not sure. All I remember was you answered questions like for math or something like that and as you ...
0
votes
2answers
290 views

VGA controller for my W65C02 computer

I´m planning to build a small computer system, based on the W65C02 from Western Design Center. This computer system should also have a VGA interface with a graphic and a text mode, defined with the ...
9
votes
1answer
276 views

Why is the Interrupt Enable Hardware Register in the HRAM area on the Gameboy?

It's something I've always been wondering: Almost all of the hardware registers on the Gameboy are placed between $ff00 and $ff7f (with plenty of gaps and empty space), the HRAM is located between $...
1
vote
1answer
474 views

How good a Cray could be as a video game console? [closed]

The stats are: https://en.wikipedia.org/wiki/Cray-1 Memory‎: ‎8.39 Megabytes (up to 1 048 576 words) CPU‎: ‎64-bit processor @ 80 MHz The 24-bit address arithmetic was performed in an add unit and a ...
13
votes
2answers
3k views

Could you use uppercase or special characters in a password in early Unix?

This article is about Ken Thompson's old Unix password hash being cracked. One line in the article intrigues: "Even an exhaustive search over all lower-case letters and digits took several days (...
56
votes
1answer
9k views

When was the famous “sudo warning” introduced? Under what background? By whom?

On all Unix-like operating systems, sudo is often provided as the standard package for executing commands as superuser (or an alternative user). When sudo is invoked by the user for the first time, ...
7
votes
1answer
414 views

Can I use the DEC VT220 composite output to connect it to a TV?

I have a DEC VT220 from 1986, it has a composite output. Works great in all its max-19200Kbps monochrome glory. The composite output plug is a BNC, and it looks like BNC-to-RCA composite jack ...
7
votes
1answer
257 views

What Apple System Monitor/Integer BASIC ROM features were removed in the Applesoft II/Autostart ROM?

In spring of 1978, Apple took the updated 6502 BASIC from Microsoft, fixed some bugs and added some new commands, and released it as Applesoft II. This was soon released as a ROM set (shipped standard ...
11
votes
1answer
762 views

On what Apple II and II+ keyboards can the ']' character be generated?

It had long been my impression that while brackets [ and ] could be displayed by the Apple II, the standard Apple II keyboard was not capable of generating them. Some time ago I noticed that on this ...
4
votes
2answers
290 views

How well can a NEO GEO theoretically run Sega´s Super Scallers Games?

The Neo Geo had a remarkable capacity to scale sprites, as we can see in fighting games, but it does not have any racing, flight or any game that simulated a non ray casting pseudo 3D to my knowledge. ...
9
votes
1answer
462 views

Any Issues with running Workbench 1.3 on a Kickstart 1.2 Amiga 500?

I own a fairly early Amiga 500 with Kickstart 1.2 ROMs, Commodore Logo key and the OCS Agnus 8371. Is this system completely compatible with Workbench 1.3? Or does WB 1.3 require Kickstart 1.3 ROMs? ...
2
votes
1answer
165 views

Mac SE tube won't come on?

My SE was working fine until I took it apart to clean it, and after reassembly the tube won't turn on, what could cause this? enter link description here
9
votes
0answers
393 views

Can anyone identify this Parallel to Serial Interface Board?

I just spent an enjoyable day at the local ham fest with my father - digging through boxes of other peoples junk. I'm a sucker for weird electronics, especially when it's in the free pile, and so I ...
2
votes
1answer
221 views

Power switch color on IBM PS/2 red vs white?

Why do some IBM PS/2's have a red switch, while others have a white switch? Does the red or white power switch on the power supply signify something about the model number, CPU, or options that the ...
6
votes
1answer
700 views

What computer has the longest uptime? [closed]

Inspired by a YouTube video I saw recently that claims a very high uptime for the computers on the Voyager probes, I was curious -- what computer currently has the longest continuous runtime? For the ...
12
votes
0answers
317 views

Oxford C compiler for Commodore 64

I kept one floppy from my Commodore 128 (which I used mostly in C64 mode), which is written Oxford C compiler. It is a 5.25" floppy. Don't ask me why I kept just this one; probably because I thought I ...
11
votes
1answer
619 views

cprintf printing invisible characters in C program on VIC 20

I want to compile and run a Hello World program in C with the cc65 compiler for an unexpanded VIC-20 model. For printing I'm using the conio.h function cprintf, since the conio implementation requires ...
4
votes
1answer
181 views

Exact tape recording format for SVI-318/328 computers

I'm looking for the exact tape data format of old SVI-318/328 computers, some kind of whitepapers explaining it. I've obtained several information from a real tape, but I don't known if the infered ...
7
votes
1answer
389 views

Why is ZX80 much faster than Spectrum on Rugg/Feldman benchmarks?

If you look at the results of the Rugg/Feldman benchmarks, shown in this Wiki entry, you'll see that Sinclair ZX80 is much faster than Sinclair Spectrum on all tests despite the fact that both ...
8
votes
1answer
275 views

Any historical references to links between JOSS and BASIC?

I only recently learned of the JOSS language, and then only through a roundabout fashion from an interview with David Ahl where he mentions FOCAL. This led me to read the available manuals for all ...
6
votes
2answers
473 views

Looking for a 90's shooter-platformer game

Back in the 90's I remember playing a 2d shooter-platformer game on my family's home computer. I sucked at the game, and as far as I remember I never managed to beat the first level. The details I ...
4
votes
2answers
268 views

Does anyone remember an early 90s side-scroller with a player-controlled ED-209-like robot?

I remember playing a side-scroller at a Babbage's at the mall (on probably a sweet Compaq; I don't think it was on a C64, an Amiga, an Apple, or anything more exotic), probably around 1993, where the ...
4
votes
1answer
306 views

Why not build an “approximate” Analytical Engine before the complete one?

From the website https://plan28.org/ and blog http://blog.plan28.org/, it seems that the original documents are scattered and hard to decipher. It might be that the plans are not even close to be ...

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