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Amstrad CPC 6128 - Key cap spring missing

Of course the unthinkable happened and I lost one cap key spring while cleaning the keyboard. I am still searching but assuming all things went south, what would be the best solution to replace them? ...
5
votes
1answer
198 views

How to identify the filesystem for an old SCSI drive?

Back in the day, SCSI was the way to go. I remember my high school having a single 5Mb Sider hdd connected to an Apple //e - which seemed awesome after endlessly swapping floppies. Not long after, I ...
3
votes
2answers
379 views

How did wave soldering work? [closed]

While it is not used as much nowadays, wave soldering was a big advance in the productivity of manufacturing electronics, compared to soldering all the components by hand. It consists of placing all ...
4
votes
4answers
345 views

Using a GSM (2G) cellphone as a modem to send code

I am quite a newbie to retrocomputing, and I don't know if such a question should be asked here. But I hope maybe some of you could help me. I started reflecting on ways to send data without the ...
3
votes
1answer
56 views

Amstrad CPC 6128 - Bench Power Supply Connection Setup

I am definitely at the very beginning of my refurb-journey and learning every step now on the way ... I struggle with the following: I saw a video by Noel's Retrolab where he troubleshooted a CPC. He ...
2
votes
3answers
122 views

First time using an Amstrad CPC 6128 Disc Drive [duplicate]

I recently got my first Amstrad CPC and started refurbishing it. Now I wonder, I saw a video, on someone using the RPM test tool for the Amstrad. I found the download online, but this question might ...
4
votes
2answers
178 views

Were there “higher level programming” macro packages for the IBM Macro Assembler?

The IBM/360 Macro Assembly language was quite powerful, allowing non-trivial compile-time string manipulation. Did macro packages exist which would facilitate programming at a (slightly) higher level, ...
2
votes
1answer
154 views

Was the ProDOS beep part of the kernel or just a commonly duplicated piece of code?

On the Apple II, system beeps were typically just the 'Control-G' beep noise. However, many ProDOS-based applications from Apple Computer abandoned the firmware-based beep routine and instead used a ...
5
votes
2answers
144 views

How does Symphonie Pro actually work?

I just happened upon this video: https://www.youtube.com/watch?v=6tNizdyx-DE It's a selection of Amiga music produced using a program I've never heard of before: "Symphonie Pro". Does ...
8
votes
1answer
279 views

What was IBM’s early attempt at an OS/2 office suite?

I definitely remember that sometime after OS/2 was introduced - while it was still in its very early days - after the breakup from Microsoft, long before Warp - IBM announced with great fanfare a ...
18
votes
8answers
3k views

Why user-assembled kits?

Many early computers were sold as self-assembly kits (you get a box of parts and an instruction leaflet and have to solder them together yourself). For example, the Altair was priced at $439 kit, $621 ...
12
votes
4answers
850 views

Did the Commodore datasette interface provide greater reliability?

Cassette, being cheaper than a floppy disk drive, was a popular storage medium in the 8-bit era. Some computers such as the Sinclair Spectrum, just provided a port to plug in an existing cassette deck....
9
votes
2answers
671 views

Did any 8-bit CPUs use dynamic memory for registers?

According to https://jamiestarling.com/project-8088-the-8088-cpu-pinout/ One thing to note – the 8088 registers are made from dynamic memory cells – they have to be refreshed. The minimum clock speed ...
3
votes
2answers
224 views

Could the 6502 have worked with an Altair-style front panel?

I have fond memories of programming the 6502, though I never did any hardware hacking with it. I notice that the Altair, with its iconic front panel, was based on the Intel 8080, and from then on, ...
5
votes
1answer
162 views

Menu in Octapolis

I have been retrogaming with Octapolis on an emulated Commodore 64. Starting up the game presents a menu offering a choice between one or two players, and between music and sound effects. But I don't ...
6
votes
3answers
902 views

Why does -z and -n exist in most shells and /bin/test?

The test command on Unix-like systems provides two special syntax forms for checking whether a string is empty or not: test -z "$foo" # the length of $foo is zero test -n "$foo" # ...
7
votes
1answer
496 views

80387 transistor count

In 1985, Intel released the 80386, a particularly complex and sophisticated microprocessor for its day, consisting of 275,000 transistors, a rather large number for the day. How many transistors went ...
24
votes
6answers
4k views

Why were pack-in games not usually incorporated on the console mainboard?

In the old days, game consoles were usually sold with a pack-in game, including some iconic titles like 2600 Combat and NES Super Mario Brothers. This makes sense; it provided clear value for the ...
6
votes
1answer
123 views

Automatic booting of SunOS 4.1.14 in qemu-system-sparc: OpenFirmware vs OpenBIOS

In a fit of nostalgia I decided to boot SunOS 4.1.4 up under emulation using qemu-system-sparc. It all seems to work, but I'm trying to remove an annoying manual step. I'm starting qemu-system-sparc ...
3
votes
2answers
224 views

What was the first vector supercomputer?

I am trying to understand the trade-offs between scalar and vector machines, the threshold of complexity/transistor count/performance at which vector machines started to make sense. As data points, ...
7
votes
6answers
2k views

Connecting a Vintage Monochrome Monitor to a Modern PC

I am considering taking my nostalgia for the eighties to the next level and getting hold of a green monochrome monitor. In particular, the nine inch monitor of the Apple IIc, but maybe something else ...
15
votes
7answers
3k views

Could a Z80 address a total of 128 KB of ROM and RAM?

In a nutshell, could the Z80 address 64 KB of ROM and 64 KB of RAM, or just 64 KB for both RAM and ROM? Unfortunately, I couldn't find an exact and a direct answer to my question while searching. ...
18
votes
1answer
3k views

What is the function of this strange IBM apparatus?

Does anyone know what kind of device this is? I found it in my late dad's stuff, probably from the 1970s. It has no number, type, model, serial number or anything else on it that could be used for ...
4
votes
1answer
182 views

Reviving a Powerbook 145B, but it still struggles to power up correctly

Some weeks ago I got a non-working Powerbook 145b for 20€ (~23USD). The first thing I did was to test the power supply, which was giving a good 7.8V. I saw that the battery was still in place and I ...
5
votes
1answer
133 views

Did any S-100 cards have multi-byte peripheral registers?

This question asks about endian issues of the S-100 bus. A peripheral card that has a register larger than one byte (e.g. a 16-bit or larger word) would need to be read/written by more than one ...
8
votes
1answer
853 views

Is there a seamless, Wine-like AmigaOS emulator for Linux, specifically for text-based programs?

After trying out FS-UAE on my Fedora Linux system, which worked quite nicely, I got to thinking. Even though when the Amiga was originally released in the middle 1980s, it was revolutionary in its ...
11
votes
3answers
673 views

How was the main mechanic of the game Qix implemented?

Qix was a quite unique Taito arcade video game that saw ports to nearly any home computing platform of its time. At first glance, the game mechanics seem to be targeted at low-performance hardware - ...
31
votes
5answers
3k views

Did IBM originally plan to use the 68000 in the PC?

One of the big turning points in the history of the industry was IBM choosing the Intel 8088 over the Motorola 68000. Given that most people outside IBM considered the 68000 preferable, there has been ...
2
votes
1answer
108 views

Intel vs Motorola device communication protocols

On this page about "An S-100 68000 CPU Board" it is said: From a hardware perspective there are some very significant differences how Intel and Motorola CPU's talk to the world. Somewhat ...
5
votes
3answers
149 views

Did 68000 on S-100 have any problem with being big endian?

The S-100 bus was extremely versatile; originally designed for the 8080, computers using it had no trouble with the Z80 as a drop-in upgrade, and it even went to 16-bit with the 8086. To my surprise, ...
11
votes
1answer
298 views

Ratio of code density between 8080 and Z80

The Z80 was (except for a handful of tiny incompatibilities) a superset of the 8080, adding a number of new instructions as well as the alternate register set. It seems therefore that it must have at ...
2
votes
3answers
201 views

Are the control characters any useful nowadays? [closed]

I asked this question on Super User, but the community at the site told me to redirect to this site. If this is again an off-topic question, do not blame me please! I am sorry if the control ...
5
votes
3answers
312 views

MS-DOS adventure game heavily based on Blade Runner, circa 1991

I'd like to identify a game I played on my first PC (x386, 2MB RAM) which I built in 1991. It was also one of the first, if not the first game I ever played on a PC. The game was heavily, and I mean ...
23
votes
7answers
4k views

Why did 8-bit Basic use 40-bit floating point?

Nowadays floating point is usually either 32 or 64 bits, sometimes 16, occasionally 128. But of course, the Basic interpreters on the 8-bit machines, having to implement floating point in software ...
10
votes
1answer
638 views

Difference between INT 0x20 and INT 0x21 (0x4C)?

Checking the MS-DOS interrupt list we see INT 0x20 "Terminate the program" (see https://en.wikipedia.org/wiki/DOS_API) but if we check the same page we see INT 0x21 with function 0x4C will &...
4
votes
3answers
337 views

What is this Intel Hexadecimal-like file format in this Tiny BASIC dump?

I am looking at this Tiny BASIC dump which seems to consist of two sections, the first being a list of symbol addresses, and the second one containing Intel Hexadecimal records with a leading space: ...
7
votes
1answer
369 views

How did old car games, using “sprite illusions”, function on a technical level?

Example: https://youtu.be/E9QJZSBpvg0?t=80 The road turns not only left and right, like in the classic Pole Position, but also goes up and down. Other than the cars and the road, there are numerous ...
1
vote
2answers
144 views

Commodore C386SX-LT, what is causing this hissing sound

I'm trying to work out what is wrong with this laptop. There is a hissing sound coming from the power board mid left. The laptop screen remains off and there is no output to external VGA unless it ...
12
votes
1answer
1k views

When did the Altair move ROM to the top of memory?

The 8080 starts running code at location 0 on reset. The natural layout of memory on a computer using that CPU is therefore ROM at the bottom of the memory map and RAM at the top. CP/M demands the ...
32
votes
2answers
3k views

What did Pete Stewart think he knew about efficient implementation of floating point denormals?

The most controversial part of the IEEE 754 floating-point standard is gradual denormals. Typically they trap to software rather than being implemented in hardware. In the common case where a workload ...
2
votes
2answers
168 views

Why did the SWTPC 6800 Computer System not take off? [closed]

In 1974, a major semiconductor company released its first 8-bit CPU that was good enough to build a serious computer around. In 1975, a smaller company built a computer around it, a horizontal box ...
1
vote
1answer
110 views

Why was the SWTPC 6800 Computer System cheaper than the Altair?

In 1974, Intel released the 8080, which basically was the first microprocessor good enough to build a serious computer around. That led to the Altair 8800 the following year, which was the beginning ...
36
votes
2answers
3k views

Was AGP only ever used for graphics cards?

Reading on the AGP spec, the little bits I've found on sites like https://old.pinouts.ru/Slots/agp_pinout.shtml, say: The Accelerated Graphics Port (also called Advanced Graphics Port) is a high-...
9
votes
3answers
707 views

ZX Spectrum 48k Power Supply outputting 15V

I got a working ZX Spectrum 48k (issue 6a) with the original power supply. Before hooking up the power supply I tested with my multimeter to see if it was good. The power supply specifies it outputs ...
0
votes
1answer
101 views

VICE loads files slowly on Fedora 32 Linux [closed]

I lately wanted to try some of the Commodore 64 games I have kept as D64 files on my Fedora Linux system using VICE. I have lately upgraded the system from Fedora 26 to Fedora 32. After I started up ...
8
votes
1answer
516 views

Why did the Altair use 100-pin edge connectors?

The Altair 8800 was based on what came in later years (much to the displeasure of MITS) to be known as the S-100 bus, because it had 100 lines, because MITS found 100-pin edge connectors were ...
5
votes
4answers
327 views

Better way to do Z80 “bank switch & call”?

I have a memory setup where the whole address space can be exchanged (default 2 slots with 2 banks each, but may change depending on "expansion cards" plugged in). Banks are switched by ...
5
votes
2answers
223 views

What were the alternative graphic cards for the Apple II?

In this question, it's mentioned the Apple II's slot 7 was used by third party graphics cards. Is there any documentation on those? What were those cards and what were their capabilities?
8
votes
2answers
2k views

Was there a way to directly print out a deck of punch cards without involving a computer?

Was there any equipment which could directly print out the program or data on a stack of punchcards, without first loading the deck into a general-purpose computer? In other words, a transfer from the ...
2
votes
1answer
149 views

How did VisiCalc decide how many decimal places to display?

VisiCalc represented numbers in BCD to be able to handle decimals precisely. But how did it decide how many decimal places to display? In some screenshots like https://www.researchgate.net/figure/A-...

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