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42 views

Pavilion N3410 won’t recognize new hard drive issue [closed]

For retro gaming, It’s a HP Pavilion N3410 I got for 22$ and wanted to put Windows 98se on the new hard drive i have (80 gb). Problem is, it won’t let me boot to the boot floppy I have with the hard ...
2
votes
1answer
112 views

Z80 - SIO/0 Frequencies

Z80 board with a SIO/0. I am struggling to understand how CPU and SIO frequencies are related, if they are at all. SIO/0 datasheet didn't help much. If I clock both the CPU and the SIO(TX/RX) from a 1....
4
votes
1answer
180 views

Apple IIc : displaying HGR page 1 in AUX memory

I need to display HGR page 1 ($2000 to $3FFF) located in AUX memory (not in MAIN memory). According to the "Apple IIc Reference Manual - Volume 1", page 45, I must first turn 80Store on by ...
3
votes
1answer
183 views

CRT Mitsubishi Diamond Pro 1000 black screen: flashes BIOS logo during boot, but otherwise black

I received this off eBay yesterday and the seller had showed images of it working. The CRT shows many signs of life, I hear static when it turns on, a sound when I switch resolutions, the degaussing ...
20
votes
3answers
7k views

What was the rationale behind 32-bit computer architectures?

Though today various power-of-2 word sizes seems to be the norm, back in the 50-60s multiple-of-6 word sizes was more popular and was required by Department of Defense(DOD) in particular. 36-bit ...
143
votes
2answers
22k views

Why does trying to break into the NT 3.1 kernel reboot my 486DX4 machine?

I installed Windows NT 3.1 on a Compaq ProSignia 3080 system, because of several reasons: I know that this machine was running Windows NT 3.1 when it was in productive use. And I think this machine ...
5
votes
1answer
214 views

Did any ZX Spectrum clones use a 16 bit datapath between memory and video generation?

On the Commodore 64, there is a 12 bit datapath between memory and the VIC II: the ordinary screen data, which is in DRAM, and another 4 bits which comes from another SRAM chip which may be paged into ...
4
votes
1answer
154 views

Did Tomb Raider on Saturn have fewer save crystals than the PlayStation port? [closed]

I've been trying to find this out for ages. Having owned the Saturn version (which was the original release, BTW) when it was new, but also playing the PlayStation version at a cousin's house, I could'...
4
votes
1answer
350 views

Why does the JSR operation not jump?

I am building a computer based on the 65C02S, and when stepping through the code, I see strange things happening. This is my code: SEI CLD LDX #$ff TXS JSR someRoutine ... This translates to this ...
7
votes
1answer
163 views

How did macro-instructions and indirect addressing interact in IBM's MAP/FAP assemblers?

The MAP and FAP assemblers for the IBM 709/7090/7094 had a nice macro facility. I was surprised by its power. (Actually, I guess it is possible that most macro processors at the time were as ...
5
votes
2answers
445 views

Was there an analog of local labels in the IBM assembly language?

In the assembly language used in Unix on DEC machines (PDP-11, VAX), one can use numerical labels and refer to them with suffixes "b" and "f" meaning "backwards" and &...
8
votes
1answer
656 views

How was “GEOS” meant to be pronounced?

GEOS was a hugely popular operating environment for 8-bit Commodore and Apple machines. It was developed and published by Berkeley Softworks, who eventually released a 16-bit version for IBM-...
7
votes
1answer
261 views

What could be the reason an `LD B, B` instruction was used in this busy loop?

The Game Boy game "Tetris" leaves a transmission interval of about a millisecond between bytes sent over the serial link, as suggested by the official Game Boy Programming Manual, to give ...
8
votes
1answer
470 views

On the video signal generated by the ULA of the ZX81

I have two ZX81, one is perfectly working and I am trying to repair the other one. After repairing the external power supply (a wire of the transformer was cut near the connector. I think it was due ...
27
votes
2answers
6k views

How did the “Programmer's Switch” work on early Macintosh Computers?

The early Apple Macintosh computers (original Mac, Mac 512K, Mac Plus) all came with a "Programmer's Switch" installed on the side. I believe this persisted for a long time, with the switch ...
5
votes
2answers
320 views

How can I tell if my old PC supports > 137 GB hard drives?

I have an old PC from 1999 that has an ASUS P5A motherboard. When I power it on, it says ASUS P5A ACPI BIOS Revision 1011 Beta 005 and 05/02/2002-ALADDIN5-<<P5A>>: I recently read that up ...
15
votes
0answers
262 views

Uninstalling OS/400 by deleting one program

This is about the AS/400 which is an IBM mini-computer launched in 1988. It lives on today after several name changes and considerable hardware and software changes. It is still often informally ...
5
votes
2answers
881 views

Were any vacuum tube computers built with wire wrap?

I'm trying to gain some understanding of how early computers were built; as discussed in What accounted for the cost of ENIAC? the cost of first-generation computers was not necessarily mostly about ...
19
votes
2answers
2k views

Z80 to x86 asm translator?

8086 is source code compatible with 8080. Zilog Z80 extended Intel 8080 with: An enhanced instruction set including bit manipulation, block move, block I/O, and byte search instructions New IX and IY ...
5
votes
1answer
173 views

Is there some simple way to avoid the artifact of “invisible” or “stuck” animation in old video games when streaming video?

I watch many live video + audio streams of people playing old video games, such as NES ones. An extremely recurring annoyance is that, for example, when the main character is damaged and is supposed ...
6
votes
1answer
276 views

Did other computer companies need to license Fortran from IBM?

Reading a fascinating online book about the history of computing, I came across this passage on http://ds-wordpress.haverford.edu/bitbybit/bit-by-bit-contents/chapter-seven/7-5-assembly-language-...
4
votes
1answer
432 views

Why ASCII paper tape has lower bit punched from the narrow side?

ASCII was presented on paper tape where the lower 5 bits cross sprocket holes as following While FIELDATA chose the other way I found placing the higher, flag bits at the narrow side appealing, ...
21
votes
4answers
4k views

What accounted for the cost of ENIAC?

I'm used to the fact that first-generation computers were very expensive, which I had always assumed was because they contained large numbers of vacuum tubes, each of which is a rather complex, high ...
10
votes
2answers
250 views

Did any core-memory computers have a read-and-erase instruction?

Magnetic core, the primary form of computer memory from the mid-fifties to the early seventies or thereabouts, had the slightly awkward property that reading it erased it, so every time the CPU ...
3
votes
2answers
186 views

How many 6SN7 tubes did it take to store a bit?

One of the most important components of a computer is a circuit called a flip-flop, which has two stable states (that it can flip-flop between, hence the name); it is used for temporary storage of a ...
1
vote
1answer
217 views

8088 CPU A16-A19 address lines go crazy with nop test after 0FFFF address

I'm building a minimal, minimum mode 8088 computer. I started with an 80C88-2 (CMOS, static variant) CPU. My configuration is really simple. One CPU, one 74HCT245 (DTR->DT/R) for the data lines, ...
39
votes
11answers
8k views

How did early laser printers get by with so little memory?

The first HP Laserjet only had 128K of memory. To print an area of 7.5 by 10 inches at 300 DPI requires 844K if it's kept as a single bitmapped image. Obviously they were doing something clever to ...
3
votes
2answers
146 views

Could early computers use existing punch card machines?

In the early decades of the industry, computers used punch cards for data storage and transmission, partly because they were already widely used for pre-computer data processing; indeed, a major ...
4
votes
1answer
94 views

Why have both the ORG and LOC pseudo-operations in the SHARE/Symbolic/Fortran Assembly Programs for the IBM 704/709/7090/7094?

This is a fairly basic question, and I almost feel ashamed to ask it; I'm guessing it can be answered in a single sentence. There was a rather influential series of assemblers for some of IBM's ...
6
votes
2answers
526 views

Why doesn't Visual6502 simulate RRA in the way I expect?

As everyone knows, the 6502 has many many undefined opcodes. One of these is RRA, which essentially performs both ROR and ADC. From what I understand of hardware (really not much) and the explanation ...
13
votes
3answers
6k views

When did they stop verifying everything that went into a computer?

In an IBM service bureau in the early 1960’s all data was keyed twice. The first time the holes were punched into cards. The 2nd time a verifier checked that the correct holes had been punched. ...
8
votes
1answer
419 views

How does Master System backwards compatibility work on the Megadrive?

I know that the Megadrive contains the Z80 CPU to help control the soundchips for 16-bit games, and that it provides backwards compatibility for the CPU processing of Master System software, but ...
5
votes
1answer
108 views

MC68030: does execution resume during or after cache burst refill?

The MC68030 processor is equipped with dual 256-byte instruction and data caches as well as a "burst" mechanism used to quickly load a cache line from RAM or L2 cache controlled by the ...
25
votes
1answer
2k views

Why was IBM's Scientific Subroutine Package superseded?

It is a familiar fact that scientific software tends to do a lot of vector arithmetic and similar, that one does not want to keep rewriting the low-level code for such, so the usual practice is to use ...
1
vote
1answer
178 views

Startup behavior of Gameboy - what to replicate in an emulator? [closed]

I'm new here. Let me know if this is the wrong place to ask this kind of question. I'm planning to build a Gameboy emulator. Before I start, I want to have a clear understanding of the startup ...
34
votes
13answers
7k views

Why were programs entered on punch cards instead of paper tapes?

Dale Fisk's Programming With Punched Cards is a fascinating account of programming in the days of punch cards. The fundamental dynamic was that early computers did not yet support timesharing. The ...
13
votes
2answers
961 views

Why does the 6502 JSR instruction only increment the return address by 2 bytes?

Currently messing with 6502 assembly on a C64, and I don't understand why the JSR instruction is so weird. According to the instruction table, JSR is a 3-byte instruction and only operates in absolute ...
11
votes
2answers
415 views

AdLib, YM3812 and Timers

For no particular reason I started reading up on the original AdLib Music Card, and it's clear that this card was little more than a stock Yamaha YM3812 music chip (aka OPL2) glued to a PC's 8-bit ISA ...
2
votes
1answer
223 views

Microsoft C 6, far pointer, cast to int, warning C4047

Trying to access one byte in memory using segment/offset, like this union REGS in, out; struct SEGS segs; int v; char _far* p; ... int86x(...,&in,&out,&segs); p = (segs.es << 16) + ...
8
votes
1answer
830 views

How many transistors in the CDC 1604?

The CDC 1604, released in 1960, was Seymour Cray's first supercomputer, and also one of the first computers made of transistors. (The IBM 7090 was released only the previous year.) How many ...
3
votes
1answer
281 views

Building a Memory Management Unit to expand the 16Bit Address space [closed]

I'm in the middle of making an 8Bit computer, I've selected Z80, the 20Mhz version, which is cheap and readily available. Since Z80 has a 16bit address line it can only address 64KB of memory location....
7
votes
0answers
365 views

What is the origin of executable compression?

According to the wikipedia article on the topic, the earliest executable compressor listed is Realia Spacemaker for IBM PC (since 1982, written by Robert B. K. Dewar, SM.COM, signature "MEMORY$&...
17
votes
6answers
3k views

Are there other examples of CPU architectures mostly compatible with Intel 8080 other than Z80?

When the Zilog Z80 was released, it was marketed as being mostly ISA compatible with Intel 8080, while also providing enhanced features. Likewise, the CPU of the Nintendo Game Boy is a custom ...
5
votes
1answer
148 views

How did games written for tape-based BBC micro, get officially and unofficially ported to disk, bearing in mind extra workspace needed by DFS ROM?

If I recall, PAGE = &E00 for a BBC Model B system with cassette tape based storage. On installation of Acorn DFS ROM (with 8271 Floppy disc controller), the ROM allocated more memory, increasing ...
5
votes
1answer
379 views

3.5″ floppy drive shown as 5.25″ in Windows 98 SE

I have an old PC from the 90s. When I boot DOS from floppy, everything works fine. I have just installed Windows 98 SE and for some reason, the 3.5 inch floppy drive is showing as 5.25 inch drive. It ...
2
votes
1answer
135 views

Apple II double buffering and double high resolution

I write programs in assembly language using HGR mode. For a fluid display, I use the double buffering technique. Is it possible to use this technique in DHGR (double high resolution)? If so, I am ...
1
vote
2answers
121 views

What is the easiest way to access/convert Lotus NSF files?

Would like to read some .NSF files (preferably on Linux). Converting to PDF ideal, but anything else that uses modern formats (eg XML) is fine. When I google "nsf viewer" I get many very ...
2
votes
1answer
159 views

How to convert series of hex digits in memory into the format for use with Applesoft math subroutines

I'm trying to write a calculator program in assembly for the Apple //e. I know that there are built-in subroutines for performing all kinds of math operations involving the floating-point accumulator (...
6
votes
1answer
646 views

Why does the VICE “load” command skip the first two bytes?

I am studying assembly of the C64, and of course using VICE to do so. VICE has the load command to load data straight into the C64 RAM. I reckoned I could use that to put machine code into RAM and run ...
4
votes
3answers
236 views

What bit depth and sampling frequency could the BBC micro play back sampled sounds?

I have an archive of sample recordings with a sample playback program, the date and author in the BBC BASIC loader for the program is "(C) 1985 by DAVID J. HOSKINS" There are are about 10 ...

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