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6
votes
1answer
599 views

Z80 ctc gold ICs speed

Does anyone have any information on what is the maximum speed for the gold ceramic z80 CTC?
2
votes
1answer
752 views

Why did this Hitachi 6301 assembler routine only work once?

I am trying to learn assembler on the various retro machines I own, or am about to buy. Today I tried converting this 8080 routine (which worked, repeatedly): | START: | MVI A,0 | 8000 | 3e | | ...
13
votes
1answer
2k views

Why does the C64 have the following palette?

The Commodore 64 has the following fixed palette of 16 colours: (Your palette may vary due to tuning of screen, etc.) What was the reason for this selection of colours? Are these colours ...
2
votes
1answer
154 views

Thinkpad 350 keyboard

Am wondering how to use the keyboard from a Thinkpad 350. There are three cables, with 6, 10, and 18 pins (but the big connector on the motherboard seems to have only 17). I assume this is a grid of ...
10
votes
4answers
1k views

How did DOS know where to load itself in upper memory?

If I remember correctly, you could ask DOS to load in upper memory by writing something like... DOS=UMB ...somewhere in the CONFIG.SYS file. But the question is, how did DOS know what portions of ...
9
votes
1answer
775 views

How do you remove an LCD bubble on an unmodified Game Boy?

On an unmodified Game Boy Pocket, a small round ~0.5mm diameter bubble appeared on the center-left side of the screen eight months after I had last used it (there was no indication of it previously). ...
5
votes
3answers
995 views

Where can I get icons for Windows 3.1/95-style GUIs?

Consider for instance the GUI for Microsoft Word 97: I am interested in getting the tiny icons used for the "Open", "Save", "Print" operations below the menu bar. Is there a good source for these and ...
6
votes
4answers
2k views

What is the (usually lower quality) “software rendering” mode visible in so many “second-generation” FPS games?

During a conversation, a friend of mine sent me this picture: It's the first Thief (I guess), with so-called software rendering. I already experienced this effect in Quake 1-2 and to an extent, in ...
1
vote
1answer
458 views

How adequate would 48-bit floating point be? [closed]

Though power of 2 word sizes look in hindsight like a natural consensus, historical computers used quite a wide variety, including but not limited to 9, 18, 36, 12, 24 and 60 bits. Power-of-2 ...
5
votes
2answers
169 views

Can fast page mode depend on the first data retrieved?

As early as the seventies, some computers used RAM in page mode, in which you can read two or more words from sequential locations in rapid succession by only supplying the column address once, and ...
3
votes
1answer
1k views

Carry flag in 8080/8085 subtraction

How is the carry flag set during a subtraction by the 8080 or 8085 processor? For addition, the carry flag is set if the result is greater than 255 (i.e. if it overflows). From the programmer's ...
46
votes
5answers
14k views

Why did C have the return type before functions?

In general, there are two types of syntax of defining functions - Something like C, C++, C#, or Java (int functionName(char arg)) vs the ML (and others) tradition of defining the return type after the ...
15
votes
2answers
4k views

Is the s-video output on the Commodore 64 different from “normal” s-video?

I saw Commodore 64 to modern TV about how to connect the Commodore 64 to a modern TV. I don't understand all the details of the answer, so I wanted to try and ask something specific here. In short, I ...
34
votes
5answers
3k views

Which ports are which on this Soviet ZX Spectrum clone?

Today I got my (first) Soviet ZX Spectrum clone. The person who sold it to me had inherited it and had no idea how it worked. It seems to be a home-made clone, rather than a factory-built one. See ...
4
votes
2answers
237 views

How to test an Orange Micro Grappler+ card?

Are there some tests that can be done to verify the operation of an Orange Micro Grappler+ printer interface card (1982) in an Apple //e? I've searched around the web and the paper manuals for ...
20
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 ...
6
votes
3answers
2k views

Getting your Commodore VIC-20, 64 or 128 online

Back in the day, of course we used modems ("dial-up modems" in today's parlance) to get our Commodores connected to other systems. These days I know several people have concocted options to get ...
11
votes
4answers
2k views

Who wrote the MS BASIC on the PET/C64/etc?

I'm wondering if anyone has a document that describes the history of the BASIC interpreters used in the various Commodore 8-bit machines? Ultimately I'm trying to track down how it is that the A% ...
5
votes
1answer
283 views

Where can I get the errata sheet for Spectrum Machine Language for the Absolute Beginner?

I'm happily working through William Tang's Spectrum Machine Language for the Absolute Beginner. I've already found one error (in the EZCODE listing), which I was able to fix myself, but to save myself ...
23
votes
1answer
4k views

Why do all the Speech Synthesizers have that same Voice?

The first time I ever played with software speech synthesis on a microcomputer (not hardware synthesis, like in TI's Speak & Spell) was around 1983, using S.A.M for the Commodore 64. A year later,...
14
votes
3answers
2k views

Why do only the low 7-bits of the R register increment?

On the Z80 the R register is 8 bits wide, as evidenced by LD A,R and LD R,A And every M1 cycle, R increments by 1. But the uppermost bit does not participate in this increment. R will not go from 0x7F ...
19
votes
5answers
2k views

Size of the PDP-8

What is the physical size of a PDP-8? The photographs I found seem to be evenly divided between showing it as a compact unit that looks maybe one foot high, and as a tall cabinet maybe five or six ...
18
votes
2answers
6k views

Was OS/2 a viable alternative for daily DOS and Windows tasks?

After playing a bit with the OS, a question sparked my interest: Could it entirely replace DOS and Windows ? Let's restrict the scope of this question a bit since it's fairly broad, Was it ...
7
votes
2answers
11k views

Best path to learn C64 assembly [closed]

The amount of tutorials, youtube videos, scanned books on C64 programming is overwhelming. What materials would you recommend -- and, importantly, in what order! -- to build a path to programming my ...
23
votes
6answers
4k views

What techniques were used to reduce the required re-rendering in 3D programs?

Inspired by this GameDev question. 3D rendering is expensive. With 2D games it's easy to not re-write the buffers every frame, like in Super Mario Bros where the PPU is instructed to render the level ...
4
votes
1answer
1k views

How did Microsoft take over Winsocks (Windows Sockets)?

In the early days of the Internet, Windows users had to install an application called "Trumpet Winsock" in order to use Internet apps like e-mail, FTP, WWW, etc. There were competitors, but Trumpet ...
2
votes
2answers
617 views

What was this old athletics game I played?

I used to play this athletics game on a really old PC. I don't remember much about it since I was probably 4-5 years old by then (1990), but what I still know is this: It was monochrome. There were ...
7
votes
5answers
655 views

When did smart terminals arrive?

In the days of mainframes and minicomputers, a common user interface was a serial terminal where each keystroke was sent to the computer, which could respond with an update to the contents of the ...
18
votes
2answers
5k views

First commercial DOS game?

What was the first commercial game sold for use on IBM/MS/PC DOS after the IBM August 12, 1981 release.
3
votes
1answer
89 views

Telebit QBlazer modem manual

Inspired by another post here, I recently purchased a Telebit QBlazer modem and am having some fun with it. It did not, however, come with a user manual, nor can I find one online. In the absence of ...
2
votes
1answer
520 views

How was the first working version of Google written?

Which language and/or server software did Google use for its initial version?
3
votes
2answers
313 views

68k macintosh lowmem system globals

While digging through a classic Mac 68k disassembly I got to the point where I need to know more about the "Boot Globals" residing in lowmem's system global variables. BootGlobPtr lives at $DDC, that'...
7
votes
1answer
499 views

Identify this Amiga game: It's just like Rocket League

I remember playing an Amiga game which was very similar to Rocket League, subject to the technology of the time. It was a two player game with a top-down 2D playing area. There was a large puck ...
11
votes
2answers
772 views

Getting started with CP/M

I have a Commodore 128, but this is a platform-neutral question. I have a lot of experience with a lot of operating systems (including DOS, Linux, BSD and AmigaOS) but I never used CP/M much back in ...
10
votes
1answer
128 views

VT50 Reverse Linefeed

The DECscope User's manual (EK-VT5X-OP-001, 4th printing, March 1977) states (page 19) that Reverse Line Feed is VT52/VT55 only: Reverse Line Feed (VT52 only) invoked by ESC I (033 111) ... However, ...
8
votes
2answers
958 views

Who were the first engineers to “cleanroom” the IBM PC BIOS?

In the first season of the AMC show Halt & Catch Fire, the protagonist "Cameron Howe" is introduced. Cameron portrays a rookie engineer who is recruited for being extraordinarily talented, and is ...
5
votes
2answers
379 views

When did the tilde first start to appear on standard keyboards?

Someone at work made a joke, "He's so old that keyboards didn't have that key". When would the ~ have first appeared on keyboards?
14
votes
6answers
2k views

Why did tactile-feedback keyboards lose popularity?

IBM spoiled me for hardware quality. I've gone through many computers, including a TRS-80, Heathkit H-89, Commodore Vic-20 and C-64, and countless PC's but my first original IBM PC will always be my ...
11
votes
4answers
2k views

PDP-8 transistor count

https://en.wikipedia.org/wiki/Transistor_count provides some transistor count figures for early microprocessors, e.g. 8008 and 6502 both listed at around 3500. The PDP-8 was a 12-bit computer with a ...
10
votes
3answers
1k views

How did the PDP-8 handle strings?

The PDP-8 was a popular 12-bit minicomputer of the late sixties. It used word addressing, so that it always dealt in 12-bit words, of which it could address 4096 with a full bank of core memory. In ...
44
votes
9answers
12k views

Why did the IBM PC need a sound card?

The original IBM PC and later variants used an Intel 8253 or 8254 as a sound chip. Why did users add sound cards such as the Adlib or Sound Blaster. I remember voice output with programs like ...
9
votes
6answers
5k views

Cannot boot from a Compact Flash card

I am trying to fix up an old work computer I have from the early to mid 90's. Everything works fine, but the hard drive makes a horrible clicking noise when it loads anything, so I decided to ...
7
votes
1answer
377 views

Reading data over serial from an old punched tape reader

I have an old GNT-4601 punched tape reader/punch that I'm trying to connect to a modern computer. Using the DTE port and a usb-to-serial adapter, I'm able to send data to the punch but I can't read ...
1
vote
1answer
369 views

What was the name and origin of this security software?

I am trying to find a free software for security, that I downloaded for tracing someone attached to my computer. I remember using this on my Windows 98 system. You could see on a map where the ...
3
votes
3answers
358 views

Was the Jupiter Ace computer ever sold by Radio Shack in the USA?

One answer is yes; I personally remember seeing it for sale at a Radio Shack store in Texas or California. In fact, I almost bought one. The Jupiter Ace was a British computer with the Forth language ...
1
vote
1answer
602 views

Where was MS-DOS used? [closed]

How widely was MS-DOS used? Was it globally, or just in some specific places? Were there any regional substitutes used more commonly, and if so, what were they?
19
votes
7answers
4k views

What video connections were common in Europe?

What video connections were common on European TVs and monitors during the "retro" era? In the USA, first there were none on TVs (RF screw terminals only) and monitors had composite (yellow RCA, CVBS)...
8
votes
2answers
725 views

ZX BASIC REM statement overhead

Since my other question has been answered and has given me a way to do high-precision timing, I've been experimenting with it a bit. The first thing I did was write a simple benchmark using the FRAMES ...
4
votes
1answer
187 views

Unexpected UL error / List problems Epson HX-20

I have an Epson HX-20 which has been in storage since I last used it in 2013. To my surprise the program I wrote back then is still stored in RAM, and by LISTing it (and checking it against the ...
13
votes
4answers
2k views

Make a BASIC TAP file readable on Linux

I am trying to convert my own BASIC TAP files (containing BASIC programs) to text so that they are readable on my Debian GNU/Linux machine. If I open them as is, I get this, which gives me some hope, ...

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