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87 views

Keys on Omnikey Inverted T Ultra

On my Inverted T ultra keyboard, the SF9 key and the number pad asterisk (*) keys perform the same function; the num pad equal (=) key and the F7 keys are similarly tied together. I don't know if this ...
0
votes
0answers
33 views

Keys on Omnikey Inverted T Ultra Keyboard [duplicate]

Omnikey Keyboard I have an omnikey inverted T Ultra keyboard. The SF9 key and the number pad asterisk keys perform the same function. The num pad equal key and the F7 keys are similarly tied together. ...
0
votes
1answer
151 views

4MHz Z80 timing and PAL video generation

Im trying to get some nice colored lines on some old Z80 system synced to the PAL screen, but having some sort of a problem. First I just need to know if my facts are right. I know that on Commodore ...
1
vote
3answers
204 views

How did control characters work in real teletypes?

Emulated terminals can accept control characters, being able to move the position of cursor, to delete a char or a word or even to clear all screen, change foreground and background colors, etc. ...
34
votes
5answers
9k views

Why did early game consoles need the TV to be tuned to channel 3 or 4?

It just dawned on me that, when I was young, game consoles like the NES and SNES, and possibly other devices like VCR's, required the TV to be tuned to channel 4. I asked around, and some remembered ...
2
votes
3answers
150 views

How can I get cl65 to include its subroutines, like pushax and tosmulax?

This question is about cc65, which is a toolkit including a C compiler, assembler, linker, etc. All targeting various 6502 computers, like the various 8 bit commodores, the Apple II and whatever else. ...
4
votes
1answer
317 views

Price of original Apple ][ in 1980?

Apple introduced the "new and improved" Apple ][ Plus in 1979, but continued to sell the original ][ until early 1981. I speculate that some customers must have chosen the original Apple ][ over the ...
10
votes
2answers
853 views

What physical size and density floppies are the intermediate-capacity options for the /F switch of the DOS/Windows/OS/2 FORMAT command meant for?

In MS-DOS 5.0 and newer, PC-DOS 5.0 and newer, Windows 9x, Windows NT 3.1-2000, and OS/2 4.x, the FORMAT command (present in some form or another in literally every single version of Q/86-/MS-/PC-DOS, ...
12
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2answers
281 views

Was the Commodore 128 movable zero page / stack and second block of color RAM actually used?

The Commodore 128 hardware allowed two things that weren't possible on the C64: Moving the 6502 zero page and 6502 stack to another place in RAM besides pages 0 and 1, and switching the CPU and/or the ...
3
votes
3answers
435 views

How to transfer the address of a data block into zero page using the Merlin 8 assembler on my Apple //e?

I've been fooling around with the Merlin 8 (v2.58) assembler on my Apple IIe and ran into a small snag. Basically, I would like to load the address of a block of data into a two-byte pair in zero ...
7
votes
2answers
722 views

What does Shift-RETURN do on Commodore's 8-bit computers?

Someone recently commented that, "a shift-Return is really different from a normal one. It moves the cursor to the next line, but does not complete an input operation." This would be interesting and ...
17
votes
3answers
2k views

x87 trigonometric instructions

The 8087 has instructions FPTAN and FPATAN, which are Partial Tangent and Partial Arctangent. The "partial" is presumably is to do with the range of the operands. For FPTAN the operand must be less ...
4
votes
2answers
232 views

IBM Mainframe APL internals?

The APL language used a unique set of characters, and additionally allowed overstriking of some characters on the terminal to form characters that were used in the language. When an APL workspace was ...
1
vote
1answer
86 views

Overstriking for APL on 3270s?

This question addressed the question of APL overstrikes on printing terminals. However, IBM also had 3270 video display terminals that supported APL, as well, and those, too, handled overstriking. How?...
3
votes
2answers
155 views

How exactly does the Apple II monitor set and use the “last opened” and “next changable” locations?

Chapter 3 of the Apple II Reference Manual describes the machine-language Monitor. On page 41 it describes certain remembered locations: The Monitor remembers the addresses of up to five locations. ...
80
votes
2answers
30k views

Is there any code in Firefox (as of 2020) that comes from Netscape Navigator?

Inspired by comments on the previous question Is it true that Netscape Navigator eventually became Mozilla Firefox? (Answer: Yes). In 1998, Netscape released a large amount of their existing source ...
2
votes
1answer
96 views

Printing on the graphics screen with lowercase/uppercase letters using CHAR command in Commodore BASIC 7.0

The CHAR command in Commodore BASIC 7.0 on the Commodore 128 allows printing a text at a given position on the screen. Other than the PRINT command, CHAR also works in Hires graphics mode. Since the ...
9
votes
1answer
514 views

Restore a BASIC program after reset or “NEW” command on a Commodore 128

A BASIC program that was deleted with NEW or after a reset can be restored on Commodore computers as long as no new programs are entered or loaded (or the computer is powered off). For the C64, the ...
0
votes
0answers
198 views

Identify World War 2 European theater PC wargame circa 1995

I am trying to identify a World War 2 European theater PC game, which I used to play on a Windows 95 PC, but probably predates Windows 95. The one thing that really stands out in my memory is that if ...
33
votes
1answer
8k views

Is it true that Netscape Navigator eventually became Mozilla Firefox?

Is it really the case that Mozilla Firefox is a modern day version of Netscape Navigator?
5
votes
2answers
395 views

How did Microsoft get away with JScript? [closed]

How exactly did Microsoft reverse engineer Brendan Eich's JavaScript, call it something else and not get a massive lawsuit in the aftermath? I understand this was a long time ago but I still wonder ...
10
votes
1answer
543 views

How does the 80287 process infinity values?

Modern x86 processors have an infinity control bit on the x87 FPU control register. This is bit 12 and it enables processing of infinity values in a manner that is compatible with the 80287 ...
11
votes
2answers
401 views

Best learning path for Apple IIe assembly language [closed]

I have an emulator up and running and access to the asimov ftp site, and I want to learn how to program assembly language on the Apple IIe. What assembler should I use (Merlin? LISA?) and what book or ...
5
votes
2answers
415 views

Where did the “LEVI” file selector/runner for the Apple II DOS 3.3 come from?

There's a fairly common BASIC program for DOS 3.3 on the Apple II that clears the screen, prints a catalog of the disk, and allows you to select files by letter to run or do other operations on them. ...
3
votes
1answer
130 views

How do you switch ROM banks on Gameboy MBC2 Cart with INLRetro dumper

I have an INLRetro cart dumper. The software for the device is incomplete and in beta form. I've been able to dump Tetris and it works (because it's ROM fits into bank 0). When I attempt to dump ...
7
votes
2answers
304 views

Floating control during bus sharing

I'm building a simple Z80 breadboard computer for my hobby. In this question I use Z80 as an example, but I think this may apply to many CPUs that allow for bus sharing. The problem is as follows. ...
8
votes
3answers
716 views

How can I access/use memory outside of the standard 1 MB address range of MS-DOS?

How do you access more memory (above the 1MB) in DOS if the 640KB of conventional memory are not enough? I have read a lot about this, but I couldn't figure out how to do this in actual code. Is ...
1
vote
0answers
141 views

First GPU with thermal throttling

Pretty much the title - what was the first GPU that reduced clock speeds when it started to overheat instead of simply locking up? Bonus points for first Intel and AMD CPUs too.
9
votes
2answers
152 views

What cables do I need to connect an Atari 130XE to a monitor and a television set?

I found my old atari 130XE, full of dust. I have the power supply but I don't have connection cables and controls. I've searched in eBay, Amazon and such for controls and there are plenty of them. My ...
4
votes
1answer
242 views

Hardware implementation of the isometric tile engine. Is it possible, did it exist?

We are talking about a hardware (and not software over hardware, as for example in some games on the SNES console) tile engine with multi-overlapping rectangular (rather than square, when the image ...
5
votes
1answer
257 views

What is the Nintendo 64 IPL3 and how could it be created by Rust developers?

I was delighted to learn there is an integrated toolchain for Rust development that supports the Nintendo 64. According to the documentation: For copyright purposes, the IPL3 binary is not included ...
6
votes
2answers
389 views

What's the timeline of Commodore diskette drives?

Commodore produced a number of different floppy diskette drive units, both 8" and 5.25", over the course of its history. Can someone provide a chronological list of the drives, their release dates, ...
3
votes
1answer
229 views

What was the history of Nanodata Corporation?

Nanodata was a Buffalo, New York company that was formed in 1971 and seems to have sold its first products in 1973. They filed for bankruptcy in 1982, though they may have carried on business for a ...
5
votes
1answer
382 views

When will the copyrights on various versions of Windows and DOS expire?

Related to question What is the best way to obtain old versions of MS-DOS and Windows? When will the copyrights on various versions of Windows and DOS expire? Once they expire I presume one could ...
52
votes
2answers
5k views

Why was the return key symbol ⏎ drawn differently from the motion of a CR-LF?

In the operating system (DOS) of IBM PCs, newlines were represented by a carriage return (CR) character, followed by a line feed (LF) character. The motion of a printer or teletype receiving such a ...
2
votes
2answers
275 views

80s game about running and maintaining a power station

Way back in the late 80s there was a game that centered around maintaining and running a power station for the local town. It wasnt particually complex or graphic.. just fun. On the lhs of the screen ...
46
votes
1answer
10k views

What is the context of the button “Is MS DOS a feminist?”

I just saw this button in the Computer History Museum, and I'm wondering what is the context? Context removed, "Is MS DOS a feminist?" is about the most non-sequitur thing I've seen.
54
votes
8answers
9k views

Could we have avoided the whole UTF-16 fiasco? [closed]

Anyone who has studied Unicode and is honest will admit that UTF-16 was kind of a mistake. It was born from the early assumption that 16 bits would be enough for all of Unicode. Then a hack was ...
34
votes
6answers
8k views

How should we interpret Dave Cutler's criticism of Unix?

Dave Cutler is well known for his contributions to operating systems, having led the effort on VAX VMS at DEC and Windows NT at Microsoft. According to his Wikipedia page, he is also known for ...
15
votes
1answer
2k views

Why did the Apple IIe use a 2 MHz-rated 6502, even though it ran at only 1 MHz?

The Apple IIe was designed to be timing-compatible with the Apple II+ so that timing-depndent software (such games and copy-protection systems) and hardware designed for the Apple II and II+ would, ...
25
votes
7answers
6k views

Purpose of turbo switch on systems unable to slow to 4.77 MHz?

I have a PC with an Intel P133 (133 MHz). The motherboard (PcPartner MB520NH) only allows for it to be slowed down to 75 MHz at the least via jumper settings, but no lower. Yet the PC's case has ...
10
votes
2answers
724 views

Is it possible to PRINT AT 23,0 in ZX Spectrum BASIC?

The ZX Spectrum BASIC doesn't (ordinarily) let you print on lines 23 and 24 to allow for user input. Is there a way around this? I found a fairly recent post that suggested I could POKE 16418,0 but ...
5
votes
2answers
274 views

Is integer arithmetic really slower than float with (early) MS-BASIC?

This question is based on a comment by Neil on another question regarding integer-multiplication: Do you have any citations for your claim that most MS-BASIC integer multiplication was done by ...
3
votes
1answer
212 views

Cray-1 functional units

The Cray-1 has 12 segments arranged in a 270 degree arc. It also has 12 functional units, so is there one functional unit per segment? There were 1,662 modules in 113 varieties, but what is a module? ...
4
votes
0answers
160 views

Teddy Ruxpin Animation Coding “Language”?

I've recently become interested in the original Teddy Ruxpin that operated by playing 8-track cassette tapes. The 8 channels on the tape were used in a creative way to ensure that Teddy's animation ...
5
votes
3answers
297 views

Did the Apollo Guidance Computer or other multi-ROM machines subdivide code between ROM chips/modules to facilitate partial updates?

The Apollo Guidance Computer had its code stored in six modules that held 6 kwords of storage each, and the design of each module was such that changing even a single bit after construction would have ...
8
votes
4answers
1k views

Imaging a HDD from DOS over Serial

I have recently fixed an old IBM Clone, which has an MFM hard drive. The PC booted up fine, but then I saw, that a few years back, I have deleted a few important files (probably by mistake). The ...
13
votes
2answers
3k views

How did I fry my SID chip?

I recently got a SID chip (8580r5) for $35 and got it playing music. I was really happy about it. I hooked up a small amp chip to the 9V supply momentarily (it didn't work, I was building that part of ...
19
votes
4answers
3k views

How did integer multiplication work in 8-bit BASIC without CPU support

I've recently been teaching my 11 year old binary multiplication, which is on the UK maths syllabus at secondary school. We have used long multiplication, eg shift and add. This has made me wonder ...
9
votes
1answer
345 views

Can you program an arcade game and have MAME or another emu run it?

I know Mame works with drivers for each game or hardware, and it checks for specific ROMs, and I guess it might check also for some checksum to verify the ROMs integrity. Is there some way you could ...

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