All Questions
5,787
questions
39
votes
2
answers
4k
views
Do any FAT8 filesystem images survive?
According to Wikipedia, the original FAT8 filesystem was developed by Marc McDonald in 1977 or 1978, as part of "NCR BASIC +6", a port of Microsoft BASIC to an 8080-based NCR data entry ...
- 1,881
-2
votes
1
answer
162
views
With reference to the Z80-MBC2 retro computer's SD card module: Is it possible to hook it up for dual access by let's say a Pi Zero [closed]
With reference to the Z80-MBC2 retro computer's SD card module: Is it possible to hook it up for dual access by let's say a Pi Zero.
So my idea is that if I could do a little hack on the SD card ...
- 99
24
votes
1
answer
1k
views
ImageWriter II occasionally prints hex dumps
I have an Apple ImageWriter II that I'm controlling directly over a serial port (Node.JS + serialport, Windows 10).
Generally speaking, it works fine. However, occasionally instead of printing text / ...
- 581
2
votes
1
answer
208
views
Need help with my Compaq Presario cm0900
First off, this is something that has been troubling me for quite a while because I am dealing with a pretty rare machine. I looked up this specific model but the computers I found were either from ...
27
votes
3
answers
3k
views
How did ZX Spectrum games loaders prevent the use of MERGE?
The MERGE command could be used on early games to load the first BASIC program block without it auto-running, but in later games, the use of MERGE caused the machine to hang. How was this achieved?
- 273
13
votes
2
answers
2k
views
Samsung SyncMaster 3 cannot show resolutions up from 800x600 despite manual saying otherwise
I am in the proud possession of a Samsung SyncMaster 3 monitor. In the reports and in the manual it says it can run 1024x768, but I cannot for the life of me make the resolution higher than 800x600.
...
- 131
13
votes
4
answers
2k
views
Can you manually load an Amiga library into memory?
I am trying to run JrComm 1.02a on my Amiga 1000. When I launch the software by double clicking the workbench icon, i get an alert telling me I need the 'explode.library V4+'. I have placed this ...
- 9,795
16
votes
5
answers
870
views
Programming languages that used degrees in trig functions?
Most programming languages that feature mathematical functions expect the arguments to be in radians. For example, sin(1) would typically return 0.841471, equivalent to sin 57.295°. But a couple of ...
- 20.5k
4
votes
0
answers
158
views
Best way to recover OS/2 1.3 installation from bad NIC driver
I have OS/2 1.3 Extended installed on a 286 and after installing a NIC driver for LAN Manager, a trap is generated during startup when the NIC driver is loaded and it halts. I suspect the driver is ...
- 331
10
votes
0
answers
277
views
What used EBCDIC code pages 1 thru 5?
For US English, the most commonly used EBCDIC code page is 37, which is one of the CECP code pages (Country Extended Code Page). The old IBM globalisation database has a 1986 copyright date for code ...
- 1,881
3
votes
1
answer
202
views
Spectrum +2A power supply capacitors replacement
I am new to the world of Spectrums, but I have a +2A which isn't powering up. I've tested the voltages on the pins of the connector and none of the voltages being supplied were even close. Given ...
- 43
9
votes
9
answers
5k
views
Why did the VT100 terminal have to be connected to a host computer if it already had a processor?
The VT100 terminal already had an 8080 processor.
So why did it have to be connected to a host computer? Why not use its processor to perform computations?
Is it because the VT100 processor's purpose ...
- 691
11
votes
8
answers
3k
views
Zip drive eject "tool"
So I am trying to manually eject a Zip disk from a Zip drive. This is not a OEM Zip drive, but one made specifically for a Pentium laptop. I went to the dollar store and bought a pack of paper clips,...
- 503
1
vote
0
answers
166
views
Was the WD1761 series binned FD1791's, or an entirely separate line?
I am wondering if anyone out there is familiar enough with the FD179x series floppy controllers to comment on whether they were simply binned FD179x's, or a separate line entirely? It seems the only ...
- 19.5k
15
votes
3
answers
6k
views
How was the @ sign added to keyboards and character sets?
Today, you need the @ character in many places, most notably in email addresses, but I suspect that when the syntax for an email address was defined, the sign was already supported in character sets ...
- 1,073
3
votes
7
answers
3k
views
Why did they switch from phone numbers to IP addresses? [closed]
Before IPv4 addresses there were phone numbers.
Why did they switch to IPv4 addresses to address devices in the internet?
I thought one reason is you need addresses in the local LAN. But I could even ...
- 391
7
votes
3
answers
544
views
Did the Sega Saturn support homogeneous transformations for graphics or only affine transformations?
Warning: My question contains some assumptions and mumbo jumbo. I attempt to learn how this stuff works and its correct terminology. And though I've implemented some of it (not all) from scratch over ...
- 6,333
11
votes
2
answers
1k
views
Did any games use the "Super Scaler" technique past Slip Stream?
Sega had a series of Arcade games in the mid to late 1980s which used what they called a "Super Scaler" technique. By scaling and rotating large numbers of sprites, they were able to do ...
- 623
30
votes
11
answers
12k
views
Has there ever been a C compiler where using ++i was faster than i++?
Please take a look at this post: Is there a performance difference between i++ and ++i in C?
There are two essential statements in the answer:
Modern compiler produce the same machine code no matter ...
- 4,670
0
votes
0
answers
206
views
HDMI to SCART - Using Mega Drive (Genesis) Mini with CRT
I have a Mega Drive (Genesis) Mini that features an HDMI output that I would like to use on a CRT TV I have with a SCART input.
Ideally I would like to convert the HDMI to RGB SCART for the best ...
- 153
16
votes
4
answers
3k
views
Did anybody use PCBs as macro-scale mask-ROMS?
Early on, even fairly small ROM's were quite useful. For example, you could fit a minimal upper-case only font for a terminal into something like 256 bytes. And that's a scale that a human could lay ...
- 2,264
3
votes
1
answer
225
views
Old steam files for Counter-Strike 1 Anthology DVD
I have acquired an old DVD titled Counter-Strike 1 Anthology that contains three games: Counter-Strike, Counter-Strike: Condition Zero and Condition Zero Deleted Scenes.
The DVD is released by Valve ...
- 665
7
votes
3
answers
962
views
Did any computer systems connect "terminals" using "broadcast"-style RF to multiplex video, and some other means of multiplexing keyboards?
Rendering a screen full of text as a video signal required a substantial amount of circuitry, especially in the era before LSI semiconductors. A device to generate display signals for a moderate ...
- 34.7k
11
votes
9
answers
3k
views
What is the best way to set up multiple operating systems on a retro PC?
I have an old Pentium II computer, and I would like to set it up as a retro gaming machine, but I would also like to play around with old distributions of Linux, OS/2 and other operating systems.
What ...
- 331
-8
votes
1
answer
317
views
Is there a reason why WIndows seems to be eternally bonded with the same File Systems? [closed]
One of the real stellar part of moving away from Billy-G's bloated legacy is that you can have an OS that has a file system that is not NTSF or FAT32. It astounds me as to how much better the Personal ...
- 6,121
27
votes
3
answers
8k
views
Why was MacOS unix certified?
As I understand it most Linux distros adhere to the UNIX specifications while only a few actually get UNIX certified. If plenty of Linux distros can happily adhere to the standard without being ...
- 6,121
3
votes
0
answers
83
views
Original DECUS version of Sumer in FOCAL?
I was sure I had a copy of Diamont's Sumer in FOCAL, but now I can't find a trace of it on my machines or online.
Does anyone have a copy of the original code?
- 19.5k
9
votes
1
answer
1k
views
Why do BK computers have unusual representations of $ and ^
While programming in BASIC and FOCAL on my BK-0010-01, I wonder why both the keyboard and the character set have unusual representations of ASCII 36 and ASCII 94?
ASCII 36: Standard:$ ; BK version: ¤
...
- 2,903
2
votes
0
answers
87
views
What encoding is this BK-0010-01 FOCAL file in?
I want to keep copies of the programs I write in BK FOCAL on my modern laptop, and in the end to be able to transfer text file programs to the BK.
My current system for transferring files between the ...
- 2,903
5
votes
1
answer
314
views
A SunOS kernel configuration file in the CSRG ISOs?
Does anyone know why there is a SunOS kernel configuration file in the 4.1c.1 BSD directory tree in the CSRG ISOs?
How to see that this file exists:
McKusick sells the CSRG ISOs. But let's face it, ...
- 620
2
votes
0
answers
169
views
What does OpenWatcom put to the CONST segment? [closed]
According to the documentation of OpenWatcom, CONST and CONST2 are read-only non-executable segments, string literals are put to CONST, and user-defined const global variables are put to CONST2. My ...
- 1,425
5
votes
2
answers
1k
views
Is it possible to write unit tests in Applesoft BASIC?
It's been decades since I wrote anything in BASIC. But I'm curious: If I were to go back and start playing around with it, would my test coverage be essentially zero percent by necessity? Or is there ...
9
votes
3
answers
515
views
ZX Spectrum - guidelines for porting to PC and more are appreciated
I want to make a surprise for my father.
Back in the 80s my father made a game for a custom clone (called Santaka) of the ZX Spectrum. I have all the digital files needed for it to work, but I'm ...
- 263
11
votes
0
answers
414
views
Is it possible to trap 387 FPU opcodes on a 287 connected to a 386?
The 8087 and 287 FPUs were designed before the IEEE 754 standard was released. Because of this, they contain some instructions which are not compliant with it. When the 387 was released in 1987, it ...
- 2,267
5
votes
0
answers
268
views
Who designed the ALi M1386SX core?
The ALi M1386SX is a 386 compatible microprocessor. I believe it was released around 1995, rather late for a 386 but since it was targeted at the embedded market (e.g. word processors and point-of-...
- 15.1k
8
votes
2
answers
6k
views
In this movie I see a strange cable for terminal connection, what kind of connection is this?
In the movie Fantozzi va in pensione (1988) I see a strange cable for terminal connection, what kind of connection is this?
seems a scsi cable, but I know the terminal is Ampex 220 and as I know ...
- 1,697
6
votes
3
answers
2k
views
Is it possible to raise the frequency of command input to the processor in this way?
In the 70's and 80's RAM chips worked at a lower frequency than the CPU.
That is, the processor worked at a frequency higher than the RAM.
We have that the CPU cannot receive one instruction from the ...
- 471
20
votes
3
answers
2k
views
What are these keys on the БК-0010-series keyboards, and what do they do?
(Picture taken from Wkipedia)
The БК-0011M keyboard has these keys across the top row:
ПОВТ (perhaps short for Повтор, which means Repetition; perhaps used for key repeat)
КТ
Three arrows which look ...
- 38.2k
20
votes
4
answers
4k
views
What is the serial protocol commonly used over RS-232 (among other links) and where did it come from?
The RS-232 standard (and ITU V.24 and V.28, which as I understand it are basically the same thing) specifies connectors (DB-25), electrical characteristics (-15 to -5/-3 V for "mark," +3/+5 ...
- 24.6k
11
votes
4
answers
1k
views
What is the difference (if any) between these two expressions in FOCAL?
I am trying to understand the 1969 FOCAL program Hamurabi in detail. The program was originally written for the PDP-8 version of FOCAL, but I am running it on the BK 0010-01 which presumably is a ...
- 2,903
8
votes
4
answers
770
views
How to read copy protected Apple II floppies / NIB images
I've got a game on Apple II 140k 5,25" floppy that does not exist in the archives yet. I would like to read it into an image. But ADTpro just shows read errors on all sectors in spite always ...
- 181
11
votes
0
answers
225
views
Anyone know of older mentions of the word "trap" for software interrupts than the IBM 704 manual from 1955?
I've dug into the origin of the word "trap" in computer engineering. The older documented mentions of the term I can find, is the "trapping mode" in the IBM 704, specifically in ...
- 819
5
votes
1
answer
398
views
SPARC coprocessor instructions
I think this is borderline retro, SPARC is in the past it seems...
I'm reading over the SPARC instruction set, which is confusing because every reference I find mixes "real" instructions and ...
- 19.5k
24
votes
4
answers
3k
views
How can a 32-bit x86 CPU start with reset vector 0xFFFFFFF0 even though it starts in 16-bit real mode?
As far as I know, x86 CPUs start up in 16-bit 'real' mode (maybe some don't).
The reset vector is 0xFFFFFFF0 (in most CPUs and in this context)
In this 16-bit real mode, we can only access 16 bit ...
- 343
2
votes
1
answer
198
views
When were the RCA CDP1804, CDP1805, and CDP1806 introduced?
RCA produced follow ups to its 1802 CPU, the CDP1804, CDP1805, and CDP1806. What years did they become available to purchase in?
- 15.1k
5
votes
2
answers
321
views
Timeline for PowerPC CPUs from various manufacturers
I am trying to assemble a timeline of PowerPC series processors. It is complicated by the fact that there were multiple manufacturers.
So far I have:
IBM POWER
1990 POWER1
1992 RSC
1993 POWER2
1998 ...
- 15.1k
18
votes
2
answers
3k
views
What does 'try again' mean in Unix v6?
I am running a stripped down version of BSD Unix V6, bkunix on my Elektronika BK 0010-01. It has a very limited range of Unix commands. The contents of /bin are:
cal
cat
clock
cp
date
df
echo
ed
halt
...
- 2,903
13
votes
1
answer
2k
views
What does MOS 6507 do in Atari 2600 when you turn it on without a cartridge?
MOS 6500 family hardware manual says that during a reset (or a start up), processor will fetch program counter from addresses 0xFFFC and 0xFFFD. On Atari 2600 this memory region is mapped to ROM, once ...
- 133
4
votes
0
answers
374
views
How did Z8000 implement mul/div in few transistors with no microcode?
The Z8000 was Zilog's entry in the 16-bit microprocessor market; it was unsuccessful in large part, as I understand it, because it took too long to debug. According to https://thechipletter.substack....
- 58.4k
3
votes
3
answers
370
views
How to redirect stderr in MS-DOS?
I am using CVS 1.3 in MS-DOS 6.22.
When I execute cvs -?, the top of the help output scrolls off my 80x25 screen.
I cannot redirect the output to file as I suspect it is streamed to stderr (eg. cvs -? ...
- 131