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2
votes
1answer
81 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 ...
2
votes
2answers
148 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 ...
0
votes
1answer
56 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?...
2
votes
1answer
65 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. ...
54
votes
2answers
24k 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
82 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
475 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
161 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 ...
32
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
295 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 ...
0
votes
0answers
99 views

How can I play MIDI with assembly? [closed]

I use DOSBOX with 8086x assembly and I want to add to my game project background music with MIDI
10
votes
1answer
493 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
346 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 ...
3
votes
2answers
286 views

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

There's a fairly common 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. This ...
3
votes
1answer
109 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
281 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
632 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
123 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
130 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
213 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 ...
4
votes
1answer
214 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 ...
5
votes
1answer
298 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
163 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 ...
4
votes
1answer
252 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 ...
0
votes
0answers
66 views

Nintendo Wii: How can I fix a Wiimote to use it a steering wheel? [closed]

I've recently purchased a used Nintendo Wii console. It came with two Wiimote units, one of which seems to be slightly defective. I notice the defect when I try to use it as a "steering wheel" for ...
52
votes
2answers
4k 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
248 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 ...
47
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.
52
votes
8answers
8k 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 ...
33
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 ...
8
votes
2answers
638 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 ...
4
votes
2answers
245 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
204 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
135 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
280 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 ...
7
votes
2answers
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
2k 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 ...
15
votes
3answers
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 ...
7
votes
1answer
257 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 ...
3
votes
1answer
157 views

What was the DEC CR11 card reader 'compressed Hollerith code' for?

In this manual for the DEC CR11 card reader controller, the controller can deliver the card content to the PDP11 in either of two forms: Column binary: the 12 rows of hole/no-hole are delivered in ...
3
votes
1answer
220 views

Original NES from UK, that I want to work in the US

I have an original NES from England that I bought in the early 90s. I just found it again in the attic, and I want to hook it up and start playing it again. However, I now live in the USA and it's ...
4
votes
2answers
294 views

Two graphics cards for retro gaming

I'm considering installing two graphics cards in my retro gaming setup (one AGP and one PCI) and was wondering if there are any drawbacks to doing so? The main things I'm thinking about are power ...
3
votes
1answer
165 views

Is there any RAM disk software available for Apple II DOS 3.3?

I have an Apple IIc with 128 KB of RAM, about half of which goes unused. Since the IIc has only one drive, it would be convenient to use some of that unused RAM as a RAM disk. I know that this is ...
32
votes
1answer
3k views

What mid-1970s to mid-1980s home computers had their graphics characters added to Unicode 13?

The Unicode 13.0.0 release notes mention among the symbol additions: 214 graphic characters that provide compatibility with various home computers from the mid-1970s to the mid-1980s and with early ...
30
votes
3answers
8k views

How much did IBM save by limiting the PC to 4.77 MHz?

My understanding is the CPU clock speed on the Intel 8088 in the IBM PC was selected as 4.77 MHz to simplify the design of the system. This despite the 8088 coming in two versions - 5 MHz and 8 MHz. ...
4
votes
2answers
166 views

ZX Spectrum scroll waiting for user input problem

I'm trying to compile a C program with z88dk for the ZX Spectrum. Using printf(), when the text hits the bottom line of the screen on line 24 the program stops executing until a key is pressed on the ...
1
vote
5answers
726 views

How binaries are generated using Punched cards? [duplicate]

I thought that punched cards already represent the code in binary since a hole means 0 and rest positions mean 1 on a punched card. But then I read that you could use punched cards to present the ...
9
votes
0answers
344 views

Why did some MOS 6502 packages have holes in them?

Someone was recently selling an early MOS 6502 CPU on Ebay (date code 0277) in a ceramic package that had a couple of holes in it. You can see them clearly (under the tape, which presumably was not ...

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