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4
votes
1answer
152 views

Does the Apple II's non-linear frame buffer layout help DRAM refresh?

The Apple II uses non-linear frame buffers for text and graphics. Rather than storing each line in sequence at lines 0-23: $400, $428, $450, $480,¹ ..., $7D0 it stores them at lines 0- 7: $400, $...
7
votes
1answer
243 views

What causes the horizontal lines at the left of the Atari 2600 screen?

I occasionally see video captures of Atari 2600 games that have horizontal bars down most of the left-hand side of the screen, as in this video of Star Voyager by Imagic: It's not clear to me whether ...
4
votes
1answer
510 views

Why was the original Legend of Zelda initially released on floppies?

The Legend of Zelda for the Famicom was apparently released in 1985 on floppies as a launch title for the "Famicom Disk Station" peripheral, only used in Japan due to the high prices of ...
18
votes
3answers
5k views

Did anyone ever put half a megabyte of memory in an Altair?

The Altair 8800 typically, at least in the early years after its release in 1975, operated with no more than a few kilobytes of memory, for the excellent and sufficient reasons that memory was ...
3
votes
0answers
218 views

Which pong console is this?

Sorry for the poor quality of the image, I'm trying to recognize the exact model of this console, you can see it on the movie "Stridulum" a.k.a "The visitor" 1978 USA at minute 00:...
1
vote
1answer
219 views

Can the window only be moved once per frame on the Game Boy?

I wanted to cover the top part of the screen to use as a status bar for a game. My idea was to use the Game Boy's window feature to do so. But I ran into a problem: The window's size is fixed to be ...
10
votes
1answer
500 views

Spin HDD up/down in DOS App?

Is there a register I can write to using a DOS based C app to spin the IDE HDD down after the app boots then back up upon the app close? Specifically I want to just put spin down/up commands in the C ...
1
vote
0answers
95 views

"PSI" bus on HP 3000

I came across a mention of a "PSI bus" in reference to late-model HP 3000 machines. I thought this was simply a typo for "PCI bus", but a google search suggests this really was a ...
26
votes
3answers
4k views

When did 5.25″ floppies exceed the capacity of 8″?

When 5.25″ floppies were introduced, in the mid-to-late seventies, they would have had less capacity than the older 8″ because, well, less area on which to store data. On the other hand, being cheaper ...
5
votes
1answer
200 views

What bit do the BBRn/BBSn opcodes check?

I am working with a W65C02S chip and it has extra opcodes, BBRn and BBSn that branch on a bit set, or bit reset. However, I cannot find on which register or memory location this check is done. When ...
24
votes
1answer
2k views

What is 'Adaptive Tile Refresh' in the context of Commander Keen?

The question Did John Carmack really invent "Adaptive Tile Refresh"? asks about the origins of the scrolling and drawing techniques used to allow an MS-DOS PC to provide a NES console-like ...
8
votes
4answers
1k views

Why Kansas City Standard (KCS/CUTS) differs from Bell 103/202/212 modem protocol?

While both were data transfer protocols serving streams at 300/1200 baud, why did they choose different frequencies, marks, modulation, and anything else? I understand that they serve different ...
0
votes
0answers
283 views

What is the origin of the "my" variable/method/et-al in didactic materials?

I think back to many tutorials and code snippets in which I have seen variables, functions, and files with "my" or "my_" prepended. What is the origin of this convention?
21
votes
3answers
3k views

What windowing system had the first size-proportional scroll bar?

I came across a link to a site that shows the history of the scroll bar. While the content of the site is pretty thin and devoid of explanation, it does show Xerox Star, Lisa, Mac, Amiga, Windows, ...
5
votes
3answers
769 views

Why has the Intel Itanium failed to take on the world? [closed]

Last summer, the Itanium has finally been discontinued, twenty years after its release. It was a promising technology, but in the end it turned out to not really be the case. Beside a few niche ...
22
votes
4answers
4k views

Why did the TRS-80 CPU have priority over the display?

The original TRS-80 had a separate bank of static RAM for video memory, so that there would be no interference between display and CPU when the CPU was just doing calculations in main memory. When it ...
2
votes
1answer
118 views

CC65 ignores request to correctly offset memory areas in output files

I'm trying to segment my C code into two distinct memory areas, one which will be flashed to a ROM chip and another which will end up somewhere else. Here is what I have in sbc.cfg (I was originally ...
6
votes
3answers
359 views

How did Apple IIe software handle 64K bank switching?

The early microcomputers were well served by 8-bit CPUs with 16-bit address bus width, but later generations of these machines tended to run out of address space, and had to resort to some form of ...
5
votes
0answers
144 views

First use of MID/LEFT/RIGHT string functions

I know that BASIC-PLUS definitely used MID/LEFT/RIGHT functions, as one can see on page 5-13 of the manual. It is worth pointing out that these did not exist in the original PDP-11 basic. BASIC-PLUS ...
30
votes
1answer
7k views

Did John Carmack really invent "Adaptive Tile Refresh"?

John Carmack is credited with making fast-paced arcade games like Commander Keen possible on an IBM-PC that had no specialized graphics controllers suited for those, thanks to the "Adaptive Tile ...
5
votes
2answers
593 views

What was the reason that the original Western NES console had a "cartridge bed" that had to be pushed down to play?

In Japan, they had the Famicom. You put in the cartridges on the top, just like with the later SNES and other consoles. But for Europe and the USA (and the entire "West"), the "NES"...
2
votes
4answers
433 views

Cheapest way to store and load small dataset in the 80s?

An extra, costly floppy drive would overkill when transferring a page of letter, storing game level data, or distributing a piece of BASIC program, and non built-in ones have to be paid. A tape ...
1
vote
0answers
92 views

Getting a loading seam to work with 2x2 metatiles

I'm working on a prototype for a scrolling loading seam similar to Pokemon where the screen scrolls incrementally by 8 pixels with each direction button press, and new tile graphics are drawn off the ...
16
votes
7answers
4k views

Have there been any instruction sets with an odd register width?

Did any early instruction sets have an odd integer register width? The reason I am asking is because all of the instruction sets I have read about (on this site and elsewhere) have had an even general ...
6
votes
8answers
441 views

Would a multi button controller have been possible on the C64?

One thing I felt letdown the C64 for many games was the lack of multiple buttons on the joystick, meaning you had to keep the keyboard nearby, (or by your foot!) So you could press space-bar or ...
8
votes
1answer
682 views

Why was Carrier Command for the ZX Spectrum superior to the C64 version?

The ZX Spectrum version of Carrier Command has 3D rendering, while the Commodore 64 version, despite a greater amount of RAM, was inferior in comparison. You open the in-game map and there's Google ...
4
votes
0answers
228 views

Game Boy interrupt handler crashes unless I jump to it indirectly

I have an interrupt handler I created, which is meant to reduce the overhead of interrupts as much as possible. Setting up the interrupt handler is done while interrupts are disabled, of course. It ...
5
votes
1answer
205 views

Can I use cartridge RAM for the stack pointer?

My understanding is that the extra cartridge RAM banks at &A000-&BFFF are battery-backed SRAM that is preserved after powering off the game. If I'm making a simple game that doesn't have a ...
1
vote
0answers
301 views

What old LCD monitor am I thinking about?

I once had a PC with an LCD monitor and I'd like to remember what model that monitor was. Here's what I remember: It was basically a beige rectangular box with right angles on all corners. Only the ...
5
votes
1answer
284 views

Identify QuickBASIC Game involving launch, navigation, and landing of rocket on the moon

I recall playing a game that I had from source in QuickBASIC (probably 4.5, but maybe it was earlier QBASIC) during the mid-to-late 90s that I keep wanting to revisit. Unfortunately, due to the ...
5
votes
3answers
443 views

Did Intel syntax for x86 assembly come from an Intel assembler?

I'm wondering where the so-called Intel syntax for x86 assembly came from. Did Intel release their own assembler for chips like the 8086 or do we just mean the syntax they used in the manuals?
36
votes
6answers
7k views

Why couldn't early C compilers handle variable declarations between statements?

In modern C, you may place variable declarations between statements: do_something(); int x; x = something_else(); However, older C compilers required that variables are declared before all statements:...
2
votes
0answers
78 views

DEC RdbStar information?

I'm putting together an article on TPC-C, and while chasing down leads its primary author mentioned the RdbStar project at DEC. As he described it, the manager of DEC's storage department (Jim Grey? ...
7
votes
1answer
514 views

What's the point of the CPS-2 suicide battery?

The CPS-2 arcade board contains a suicide battery that will force the board to kill itself when it runs below a certain power threshold. Supposedly this was created to mitigate piracy of the games, ...
4
votes
2answers
744 views

How could/can there exist NTSC->PAL converters for SNES and other classic game consoles?

Re-reading my old video game magazines from the mid-1990s, there's constant mentions of "USA import" games which were not released here and which "require an adapter". Many of the ...
33
votes
4answers
5k views

Why was manual branch suggestion abandoned?

Once pipelined CPUs became common, a common issue arrived as a result of taking the wrong branch of a conditional jump, and thus needing to flush the pipeline. As a result branch prediction mechanisms ...
69
votes
2answers
14k views

Why does the infamous "ENGAGERIDLEYMOTHERFUCKER" Metroid password break NES emulators?

For those who are unfamiliar, the original NES Metroid was one of many NES games to use passwords as a means to save progress. Later, this password system was leveraged to create unusual effects in ...
8
votes
0answers
246 views

How is the ‘Coprocessor segment overrun’ exception supposed to be handled?

The Intel 80386 CPU didn't have an on-board x87 FPU (maybe with the exception of some non-Intel clones). It was, however, able to use either a 80287 or 80387 as an external FPU. When the x87 FPU ...
5
votes
2answers
250 views

Did any computer ever signal floating-point overflow purely with a sticky flag?

Every implementer of floating-point arithmetic, needs to think about how to signal overflow. One possible way to do it is by raising an exception, though this creates the problem that 'exception' can ...
17
votes
3answers
3k views

In x86 real mode, how does BIOS know what hardware is present?

I know that BIOS is obsolete, hence why I'm asking here :-) BIOS needed to do things like start loading the OS, for which it (usually?) would have needed things like a hard disk driver. However, BIOS ...
18
votes
2answers
2k views

Why do drives occupy memory on Amigas

I was reading this question, and it sparked an old memory. I had an Amiga 600 a long time ago. And I used to play Secrets of Monkey Island on it, great game. But then I upgraded the computer and ...
9
votes
1answer
348 views

McDonnell-Douglas 16-bit microprocessor?

I've been working on the NatSemi PACE article and I'm trying to track down a bit of trivia... someone inserted a statement: McDonnell Douglas produced a classified military 16-bit processor called ...
3
votes
0answers
103 views

Looking for a multiline text gadget for Intuition on a 1.3 Amiga

I've come to understand that Intuition, the GUI framework on the stock A500 has 4 types of gadgets: 'boolean' - checkboxes and buttons 'Proportional' - sliders string inputs integer inputs I'm ...
13
votes
2answers
2k views

If a PS/2 device on a 32-bit x86 sends a byte to the IO port 0x60 and you read it, what happens next?

I'm writing a hobby OS and the first thing I want to do is access PS/2 devices (it's a somewhat legacy, 32 bit OS, so I figured it's relevant to ask here?). I can see my PS/2 devices and I want to ...
24
votes
11answers
10k views

Why weren't 80s arcade games programmed in C?

I know many arcade games from the 80s were programmed in 68000 assembly. This carried on probably well into the 90s, even though Motorola C compilers existed in the 80s. Why then weren't C compilers ...
12
votes
1answer
2k views

What is purpose of the “CH” button and “CH” switch position on this calculator?

What is purpose of the CH button and CH switch position on the Omron Elite 8002 Taschen-Rechner? (For those who don't know German, “Taschen-Rechner” just means “calculator”.) The switch has three ...
16
votes
1answer
3k views

How did Legend of Zelda: Oracle of Seasons/Ages know it was running on a Game Boy Advance?

I remember finding out there was a secret area in both games that you could only get to if you were playing on a Game Boy Advance. Even the 3DS releases don't allow access to them. My question is, how ...
11
votes
2answers
457 views

Was `wchar_t` ever widely adopted by the Unix culture in actual practice?

My very rough understanding of character encoding history as it relates to the Unix family of platforms/languages is that: They started using single-byte (7/8/9-ish bit) character sets like ASCII/...
3
votes
2answers
259 views

Looking for Popular Mechanics issue on BASIC

I remember being captivated as a teenager by an issue of Popular Mechanics that introduced the BASIC programming language. It would have been late 70's or early 80's. Anyone know how to find which ...
8
votes
1answer
1k views

Why does the Z80 JP (absolute) instruction always take 10 states to execute?

I've looked at a few different websites and they all agree that a JP nnnn instruction (where nnnn is a 16-bit address) always takes 10 states to execute. According to what I've read, all of the ...

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