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5
votes
1answer
332 views

How many hours of labor did it take to assemble a minicomputer?

A minicomputer like the PDP-8 contained several thousand discrete transistors and other components, all of which had to be soldered by hand, and that was among the simplest computers on the market; ...
53
votes
7answers
9k views

Why did the MS-DOS API choose software interrupts for its interface?

Access to the DOS API was done through the INT 21h x86 instruction. This was always counter-intuitive to me, coming from 8-bit systems that accessed system services by calling subroutines through a ...
4
votes
5answers
492 views

Z88DK ZX Spectrum “%f” printf not working

I'm attempting to compile a program in C for the ZX Spectrum using Z88DK. However, I'm facing an issue when trying to use printf to print out the value of a float. The code I'm trying to compile: #...
14
votes
2answers
1k views

DEC Alpha: why no 8/16-bit load/stores?

The first version of the DEC Alpha had no load/store instructions for 8 or 16-bit values; if you wanted to deal with data of such sizes, you had to do it by shifting and masking values in registers as ...
0
votes
2answers
154 views

How did the 6800's comparison operations work?

Does anyone have a quick primer to the way the 6800's compare-and-branch instructions worked internally? I'm referring to the instructions like BLS that compared a value in memory to the accumulator. ...
1
vote
2answers
189 views

How to get rid of keyboard latency in atari800 emulator?

I use the atari800 emulator v. 4.2.0 on windows 10 and linux in latest version. (https://atari800.github.io) I notice an annoying keyboard latency of up to 100-200ms (keypress-to-click and ...
-1
votes
4answers
406 views

Was it true that Microsoft actually created software for early Apple devices?

Is it really the case that there was a port of Microsoft Word and Excel that was one of the first really successful software to feature on a Apple device? Did Microsoft software actually have a ...
4
votes
4answers
361 views

What was the DEC Type 30 vector graphics display used for?

The DEC PDP-1 had, unusually for its time, a vector graphics display. According to https://en.wikipedia.org/wiki/History_of_Digital_Equipment_Corporation Most systems were purchased with two ...
50
votes
7answers
20k views

Why was the Kickstart 1.x “Insert floppy” graphic so bad?

Anyone who used an pre-Kickstart 2.0 Amiga will be very familiar with the "Insert Workbench floppy" image: I realise that this is subjective, but the image has always stuck me as ... well, a bit ugly....
2
votes
1answer
269 views

How to configure NETWORK and TCP on a DOS VM

I'm trying to install and use the Arachne broswer under DOS (6.22). I've DOS installed on VirtualBox VM (5.2.34) under Linux Ubuntu (4.15.0-88-generic #88-Ubuntu). I'm in trouble in configuring ...
8
votes
2answers
1k views

What was the first computer malware that could infect Mac systems?

The number of malware that can infect Mac computers has increased significantly last decade (2010-2019), particularly scams (including tech support scams) and fake anti-malware apps. since when ...
1
vote
1answer
91 views

Exit NitrOS9/OS9 EDIT command without saving file

NitrOS9 is a modern clone of the original OS-9 operating system used on the coco3. Both OS-9 and NitrOS9 have an EDIT command, a line-based text editor. As far as I know, EDIT works the same in both....
2
votes
2answers
224 views

How fast did the ARM-1 access memory?

The ARM-1, an early 32-bit RISC CPU, was used in the Acorn Archimedes computers, released in 1987. Its rated speed was one 32-bit instruction per cycle at 8 MHz. Typical RAM chips at that time would ...
18
votes
4answers
5k views

Were there any 8-bit CPUs with 24-bit addressing?

Or was that something that didn't appear until later CPUs (around the time of the 286 maybe)? Also, how would I go about researching this on my own? It's not exactly something I can look up on ...
18
votes
3answers
4k views

Are pixels on the Commodore 64 square?

Are "tile pixels" the same size as "sprite pixels", and are they both square (ignoring the rule that multicolor sprites can only be colored in groups of two pixels)? By "square" I mean that the ...
1
vote
0answers
602 views

How many Amiga 590 units were sold?

The A590 was an external hard disk for the Amiga 500, in 'sidecar' form factor, that could also hold an extra megabyte of RAM. How many 590s were sold, throughout its life?
4
votes
7answers
453 views

Static memory partitioning

Does anyone know of any operating system that used static memory partitioning: contiguous physical memory allocation with one process per partition, one partition per process, partitions generated at ...
9
votes
4answers
3k views

Is it possible to swap the Apple //c's monochrome CRT tube for a color one?

I just love the Snow White industrial design language of the Apple //c, especially when paired with the Monitor //c. It is a classic design that doesn't show its age. I've even recently seen them ...
2
votes
1answer
203 views

When first CMOS versions of Z80 became available and were they ever used in (non-portable) home computers?

When Z80 first became available on the market in 1976 it was made using NMOS technology. It is the version that is likely to be most familiar to people interested in retro-computers. For example, to ...
25
votes
7answers
7k views

What is the reason the 8051 was not used in 8-bit computers?

The 8051 is a Harvard-based microcontroller, but it allows us to connect external memory and simulate von Neumann's architecture. What is the main reason it was not used widely in 1980s home computers?...
8
votes
2answers
878 views

When was DEFUN added to Lisp?

I don't see DEFUN in a ~1966 copy of PDP-6 LISP. I do see it in a 1972 Maclisp. AI memo 116A from 1967 doesn't have DEFUN. (It does have MACRO.)
10
votes
3answers
1k views

How to use rounding with 6809 multiplication

The MC6809 is unusual for an 8-bit processor of its era in having a hardware multiply instruction. MUL multiples the 8-bit unsigned integer in the A register with the 8-bit unsigned integer in the B ...
14
votes
2answers
754 views

Does the Z80 allow interrupts after processing and ignoring a 0xdd prefix?

I read here that if the Z80 encounters e.g. multiple 0xdd prefixes in sequence, for each 0xxdd except the last it acts almost like a NOP, but does not allow interrupts to occur immediately after "...
9
votes
1answer
236 views

How can slot 1 of the Apple ][ replace the keyboard?

Nick Westgate posted a comment a few years back on a question about how slot 7 was unique stating that "Slot 1 on the //e is also unique - it can be used to replace the keyboard". What was it about ...
4
votes
1answer
318 views

Origin of “640K RAM is enough” quote

Yesterday I was digging through a rather long directory path to watch an episode of Fist of the North Star (on Windows 8.1) when I was hit with an error message: The path name is too long I looked ...
6
votes
1answer
377 views

Why did the Sinclair QL keyboard lack a Delete key?

Reference: picture at https://en.wikipedia.org/wiki/Sinclair_QL It seems like an odd key to omit, given how frequently used it is and given that both the Spectrum + and 128 have one, which acts like ...
11
votes
1answer
855 views

Difference between Intel 8087 and 8089 opcodes

The 8087 floating-point coprocessor presumably used different ESC codes to the 8089 input/output coprocessor, since then they would be able to listen over the bus for their own ESC instructions. The ...
3
votes
2answers
167 views

Are there Commodore BASIC 7.0 music demos?

Commodore BASIC 7.0 that came with the Commodore 128 provided commands for playing music notes and setting different instruments. The play function even had a feature that played a note in the ...
38
votes
5answers
9k views

Apocryphal (?) tale of hard drive platter propelled through a wall?

In the mid-1990s while a student at a US university during a computer science lecture, my professor (not a TA or grad student) told us a story of "witnessing" a large, then old-fashioned metal hard ...
0
votes
1answer
107 views

How is the LCDC (LCD Control) register manipulated on the Gameboy?

I don't see it listed anywhere in the 0000-ffff address space. Is it controled by the CPU? Or something else entirely?
16
votes
5answers
5k views

Why did the Z80 with 4-bit ALU out-perform the fully 8-bit Intel 8080?

Looking at the development and architecture of the Z80, it appears to be a scaled-down, cost-reduced (in terms of total system cost), clone of the Intel 8080. It only used a 4-bit ALU. I assume this ...
1
vote
1answer
122 views

Can I connect a Sega Megadrive or Genesis to an Amstrad Cpc monitor?

I'd like to buy an old Sega Megadrive, aka Genesis outside the UK. However I don't have a TV or computer monitor to view the graphics on. I do however have an Amstrad Ctm644, which is a 15Khz CRT ...
2
votes
1answer
79 views

What was the last of the Thinkpad X series with replaceable RAM? [closed]

I know my x230 has replaceable RAM. I know the x395 lists its ram as being soldered. What is the last of the X series lineup with user-serviceable RAM?
7
votes
2answers
455 views

How to pass data pointer to subroutine to use with Absolute,Y addressing?

I may be going about this the wrong way, so sorry if it is wrong, I'm coming to 6502 after 32 years (when I was 8 years old !) I want to pass a pointer to some data, either data1 or data2 to a sub ...
3
votes
1answer
95 views

Microware OS-9 assembler warning with no message

My 6809 assembly language program for the coco3 is causing the assembler to issue a warning with no message. How can I find out why the warning is being issued? From the assembly listing, showing ...
4
votes
3answers
791 views

What were some of the earliest common webservers and how did they work? [closed]

And by Web server I mean actually web server (not BBS), meaning it had to run on the actual IP internet and be browsed with a dedicated browser program. So what kind of tools were used in the late 80s/...
1
vote
0answers
54 views

Thinkpad 380E keeps shutting down randomly [closed]

Recently, I got a 380E from ebay. Seller says that it has boot error and not working, but the error was typical 161/163. I've replaced nee BIOS battery, and error was gone. After that, I formatted ...
4
votes
1answer
100 views

Why does MS-DOS 5.0 EDIT hang on my XT-class machine with a German 102-key keyboard?

Most times whene I call EDIT on my XT-class machine with MS-DOS 5.0 installed on the hard disk, the menus of EDIT appear, but the window that should contain the file contents stays blank and the ...
3
votes
2answers
254 views

What's the Motorola microprocessor with two sets of registers to avoid costly context switch?

I remember reading somewhere (maybe on Hacker News or Lobsters) that Motorola made a microprocessor some decades ago with two sets of registers. This means when handling an interrupt, it does not need ...
19
votes
6answers
1k views

Sound driver for DOS or Windows 3.x that used the PC speaker?

Long ago in a galaxy far far away, back in the early 90's, I worked for a crappy clone company as a phone technician. At the time, 386SX/25's were common for in-house technical support / customer ...
2
votes
1answer
94 views

For TRS-80 Color Computer joystick buttons, is it correct to check the first or second bit of the value at PEEK(65280)?

The Color BASIC/Extended Color BASIC “Getting Started” manuals say that to find out if a joystick button is pressed, to PEEK in location 65280. The value 255 means neither button is pressed; the ...
31
votes
18answers
9k views

Was it possible to listen to music and work on old PCs? When was it possible to for the first time?

I was wondering the other day, would it be possible to listen to a midi on a C64 while writing a program or something. I mean it did have a sound chip that would technically just get some new buffers ...
2
votes
2answers
196 views

Could Apple II cards be used on any 6502 platform?

Looking over the Apple II expansion card pinout, it seems it's largely just the pins of the 6502 plus some +12V supplies and such. Generally speaking, though, is there any reason any other 6502 ...
7
votes
2answers
1k views

Did general purpose I/O controller chips come with fewer than 40 pins?

I'm aware that 40-pins was a high-water mark for dual-inline package chips for a significant time; many CPUs of the early 1980s (8086, Z80, 6800, 6502, etc) used 40-pin packages, but no larger. ...
11
votes
3answers
393 views

Shape of Cray-1

One way the fast speed of the Cray-1's CPU was achieved was by keeping the wire lengths short. How did the C-shape of the Cray-1 help here? Were the speed-dependent portions on the inside edge where ...
4
votes
1answer
313 views

What was the purpose of exotic modes and sectors for CD-ROM?

(I ask the question again, one suggested SuperUser, but I was right, it has been closed instantly.) There are well-known sectors and modes for CD-ROM medias: CD-DA: for storing music in a digital ...
4
votes
1answer
195 views

YMODEM specification problem?

I'm looking over the documents for YMODEM found here. Scroll down to page 8, the section on 1-k blocks. Note that the protocol can switch between 1024 and 128 bytes by sending an STX or SOH. Now ...
26
votes
4answers
6k views

Unix Haters Handbook - guaranteeing synchronous, atomic operations

I've come across Filesystems with versioning and have been reading through the Unix Haters Handbook, linked there. I came across page 85: On the other hand, techniques for guaranteeing synchronous, ...
1
vote
0answers
73 views

When and with which system or software was IBM's system of tape headers (VOLx, HDRx, …) introduced?

Background: IBM compatible tape structure (*1) consists of a series of label blocks describing the volume and each file (Data Set). Essential the structure looks like this: VOL1..9 Volume header ...
0
votes
2answers
158 views

Handheld Systems Archives CD-ROM

Does anybody know if this is available anywhere? The domain seems to be gone. Clarification: this magazine was published in the 1990s. According to worldcat.org a couple of US uni's have copies, but ...

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