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40
votes
4answers
8k views

Is it true that Pentium III was faster than its successor Pentium 4?

My friend told me that earlier iterations of the Pentium 4 were not as fast as the Pentium III, but he didn't have sources. Is it true that the Pentium III was faster than its successor Pentium 4?
3
votes
2answers
162 views

How to get into Apple BASIC prompt on an Apple IIc?

I just picked up a used Apple IIc. For some reason all I get when I boot is Check Disk Drive on the screen, even with a bootable disk in the internal drive: I cannot even get the system to read the ...
7
votes
2answers
152 views

How long should I expect the Apple IIc self test to run?

I purchased a vintage Apple IIc computer and I want to make sure there are no failing components. I booted up the computer while pressing both Apple keys (open and close) at the same time. The ...
5
votes
3answers
381 views

What were the Major Public Access Unix Systems Available in the 1980s-90s?

Back in the 1980s-90s, using a UNIX system required running expensive servers or paying for timesharing service, so they were beyond the reach of most individuals, and only available to members in ...
45
votes
2answers
10k views

Why does the 80486 take longer to execute simple instructions than complex ones?

The 80486 processor can execute many instructions in a single cycle, such as a register-to-register add instruction (ADD EAX, EBX, for example), which one would generally assume is fairly complex, ...
20
votes
4answers
2k views

How did 68k-based Macs (or other contemporary systems) detect how much RAM was installed?

If I upgraded, say, a Macintosh II with larger SIMMs, naturally the machine detected that additional RAM. But how did it perform that check? Does it simply sweep all addresses until it fails? Or ...
6
votes
0answers
250 views

Did Nintendo pay WDC for their use of the 65816 core?

When Nintendo used the 6502 core in the NES (as part of the Ricoh 2A03/2A07 microprocessor and sound generator), they circumvented the 6502's patent protection by disabling the BCD arithmetic. As a ...
18
votes
3answers
3k views

What happened to the 65832?

In his June 1985 foreword to Programming the 65816 by David Eyes and Ron Lichty, Bill Mensch expresses his hopes for a 6502-derived 32-bit microprocessor: the 65832. WDC is still thriving, but the ‘...
9
votes
2answers
430 views

How do I tell vasm to allow white spaces?

I have recently been learning to use vasm. For those that don't know, vasm is a cross-platform assembler for multiple types of processors such as the M68000. http://sun.hasenbraten.de/vasm/ I am ...
3
votes
1answer
75 views

Where can this “boot.B” file be coming from on this Spectrum TR-DOS disk image?

After working on some tools that parse the TR-DOS disk image format .TRD files for a while I just noticed that one of the game disk images I had downloaded "La Abadia Del Crimen", only has three files ...
11
votes
3answers
314 views

Do any 6502 assemblers have better support for self-modifying code?

I find I keep on doing things like this: raster_interrupt: bgnd_color = * + 1 lda #$00 sta $d021 ; rest of interrupt handler so that I can do this kind of thing elsewhere in my ...
2
votes
1answer
95 views

Are there open source Java libraries for reading DSK and EDSK disk image files as used by Amstrad and Spectrum +3 emulators?

I've been working on some modules for the Ghidra reverse engineering tool. Ghidra is written in Java, which I'd always avoided when I was more actively programming so this is an opportunity to learn ...
3
votes
1answer
560 views

Problem reading 720KB floppy disks containing dat [closed]

I am using a USB connected "Sabrent FD-05PUB" 3.5" floppy drive to read data using Windows 10 computer. It shows in Device Manager as "TEAC USB UF000x USB Device" The 1.44MB disks read just fine. All ...
7
votes
5answers
1k views

Positive/negative 16-bit integer formats in 8-bit systems?

While considering the recent question on Integer BASIC, a thought arises: Most systems using/supporting integer math used a 16-bit signed format. In the case of Integer BASIC, this leads to odd-...
13
votes
4answers
3k views

Which are the earliest real-time text editors?

A real-time text editor is a program which facilitates editing text. In the process, the text is displayed on a screen, and the displayed text is updated after each key press. A commonly cited ...
3
votes
1answer
117 views

Please Identify this Apple II Diagnostic Message: “IOU FLAG E5: 1 2 3 4 8”

Does anybody know the meaning of this message from the Apple IIe diagnostic? IOU FLAG E5: 1 2 3 4 8 What are addressing the 1 2 3 4 8? I’m pretty sure that IOU is the I/O chip, E5 is the location ...
0
votes
1answer
154 views

How picky are CRTs about power cleanliness?

How picky are CRTs about the 'cleanliness' of the mains power? Cleanliness referring to electrical noise from thing like ac motors in fridges, powerline ethernet, etc. Cleanliness is also referring ...
4
votes
1answer
197 views

What sort of protocol did Soviet P6 cruise missile data links use?

I was watching a video on a Soviet submarine armed with the P6 cruise missile: https://youtu.be/9LiZGdXBw3I?t=156 The video mentions "It could use the lead missile in the group to find targets and ...
17
votes
1answer
1k views

Will disassembling an 8080 program as Z80 code work?

The Z80 is "binary compatible" with the 8080. It adds a bunch of new instructions, but places them all in unused (well, undocumented) opcodes. Does this mean that if I disassemble an 8080 program (...
3
votes
1answer
77 views

How to pass a value to an inline assembler script in a #define macro in cc65

I'm trying to add a compact #define macro in a cc65 program for performing various low-level tasks efficiently. For some of the macros, I need to pass a non-constant value to the assembler part. I ...
12
votes
2answers
2k views

How did malware spreading through PIF files work?

If you've used legacy Windows, you probably know about program information files aka PIF files. At some point, when Internet usage became widespread, these files became a vector of infection for ...
5
votes
2answers
442 views

Does Sinclair Spectrum BASIC have a maximum length for one line?

I was just writing some junk Speccy Basic programs, more to see how they take up space on the +3's disk layout than to do any actual programming. But I noticed that after editing a program line to ...
0
votes
2answers
215 views

What is the brand and model of this AT chassis case from the early 90s?

A friend is trying find the original brand and model of this old 1990’s generic case. An ad from computershopper would help.
29
votes
3answers
10k views

Why do PCs boot in 720x400 resolution?

Using my 21" Trinitron OSD, I can see that the resolution at boot is 720x400. From memory, this weird resolution is extremely uncommon if ever to be seen as a choice on software that supports ...
3
votes
2answers
452 views

What was a “Windows protection error”?

Back in the day, I had a Windows 98 machine (don't recall the hardware right now) and sometimes it would crash with the "Windows protection error. You need to restart your computer" error. So, what ...
8
votes
1answer
219 views

6502 False Reads and Apple II I/O

The 6502 series of CPUs has an interesting quirk: indexed loads and stores may perform a "false read", reading from the target address or a different address on a previous page. There are situations, ...
11
votes
8answers
5k views

Why were optical drives not used as secondary storage instead of magnetic drives?

What prevented optical drives from being used as the dominant secondary storage like the magnetic disk drives, in PCs? Was it entirely technical limitation or other issues like late development and ...
3
votes
1answer
167 views

Commodore 64 board dimensions

What are the dimensions of the C64 motherboard? I am specifically asking this because I am considering using a 64C case (these still seem to be in production) for an 8-bit homebrew machine. I wonder ...
16
votes
2answers
2k views

What are these weird long ISA slots on this 386 board? (not VLB)

In this image, you can see, from the right, a 16-bit ISA slot (occupied by a controller card), an 8-bit ISA slot, four more 16-bit ISA slots, and two of these strange slots that look like a 16-bit ISA ...
0
votes
1answer
394 views

What's the name of this CRT monitor?

What's the name of this output retro gaming monitor device? The following is a still from the Netflix production of 'Bandersnatch', a 2018 interactive movie, set in Britain, mostly in the year 1984. ...
14
votes
1answer
226 views

Is the “IBM standard character set manual” around?

From Wikipedia's code page article: Originally, the code page numbers referred to the page numbers in the IBM standard character set manual Is any version of this publication available? I'd be ...
39
votes
4answers
3k views

What was the design rationale behind multi-port and multiple connections (and back-connections) designs of the early protocols like NFS or FTP?

Originally, the FTP protocol connected back from the server to a client to actually transfer files through that new connections. 14 years later after the introduction of the FTP, the 'passive mode' ...
0
votes
1answer
93 views

How exactly does Leningrad contend the memory?

From what I understand of this answer, the Leningrad delays the Z80 during the M1 cycle so that the video generation circuitry can do its thing. I can see how M1 is "latched" (don't know if that's ...
12
votes
1answer
557 views

Odd tokenizing in Integer BASIC

While researching the underpinnings of Integer BASIC (IB), I came across an oddity I'm hoping someone can explain. Unlike MS-derived systems, IB converted numeric constants to their 16-bit ...
1
vote
1answer
131 views

How does the Spectrum +3 know how many files are in the disk's directory?

The Spectrum+3 uses a version of the Amstrad and CP/M disk layout. The Speccy version has a directory at the start of the disk after any reserved tracks and it can hold up to 64 files. Each ...
39
votes
1answer
7k views

What warning was given on attempting to post to USENET, circa 1990?

I recall a confirmation/warning message that read something like "this will post to thousands of sites... are you sure?" What was a typical such message in the days of pay-per-minute dialup access?
1
vote
0answers
143 views

Thinking through the design of a TTL video card: what memory chips and how to manage memory? [closed]

Inspired by Ben Eater's "Let's build a video card" aka "World's worst video card" two part projects on YouTube, I was inspired to consider designing a display adapter for my passive backplane TTL mini-...
27
votes
2answers
9k views

What is this programming language having PROC, DCL, LABEL keywords?

A 1980 paper called "Register Allocation via Coloring" contains something that looks like source code: P: PROC(MODE); DCL MODE BIT(1), (A1,A2,A3,A4,A5,A6,A7,A8,A9,A10, B1,B2,B3,...
10
votes
1answer
292 views

How did ZX81 assembly debuggers implement breakpoints?

What techniques were used for implementing breakpoints on the ZX81? Traditionally for the 8086 int 3h is used, for the 8080 on CP/M with DDT RST 7 as single byte replacements, 6502 has the BRK ...
1
vote
1answer
292 views

Were all NES games 16 kibibytes or less?

While searching on the Internet and Quora, I found disassemblers for Pac-Man, Galaxian, and Super Mario Bros. The thing that puzzled me, was while Super Mario Bros was arguably quite a complex game ...
3
votes
1answer
320 views

Is there any virtual hard disk driver over serial port?

NOTE: I'm not looking for a way to transfer files from Linux to DOS over Serial cable Is there any MS-DOS driver to enable a new hard-disk drive (let's say D:), using a disk image on another ...
2
votes
1answer
189 views

Who built the first electric/electronic adder?

The first electricity-based adder presumably used relays. (The electromechanical relay was invented for the electrochemical telegraph for repeaters in 1831 by Joseph Henry (1797-1878). I can't figure ...
9
votes
7answers
1k views

What are principles of vector CRT display? Simplest way to drive CRTs?

I am into playing with TTL to build 1970s style minicomputers. Aside from talking to them via some serial (or parallel) I/O port to a terminal, I am wondering about display output. This here is about ...
5
votes
2answers
445 views

What effect does exiting a FOR/NEXT loop early have on the TRS-80 Color Computer?

I have a subroutine with a for/next loop in Extended Color BASIC on the TRS-80 Color Computer that I would like, sometimes, to return early from. That is, to return from the subroutine from within the ...
3
votes
1answer
136 views

How to connect a Dragon32 to a HD TV?

The Welsh computer has a coax output and a resolution of 256x192, can I expect this to display at all on my Philips 50" 4K TV using the same input?
6
votes
1answer
325 views

What role does the 4-bit shift register play in the Leningrad video generation?

The Leningrad contains a shift register1, which I believe is loaded with data from the bitmap. This part loads 8 bits in parallel, and shifts each bit out in turn on the rising edge of a clock signal. ...
3
votes
2answers
239 views

How do I install Windows 9x on an older machine from a flash drive (or any other unconventional device)

Windows 9x is no longer common, and isn't commonly supported. While there exist many solutions to burning ISO to USB or other storage device, most fail at some point, with commonly useless if any ...
17
votes
3answers
3k views

Was there any automated unit testing prior to 1972?

Prior to 1972, was there any automated unit-testing? Did any assemblers include a testing a framework? I can find some academic journals on this topic from the late 70s -- most of which I don't have ...
0
votes
0answers
87 views

Siemens PG675 monitor problem

I have been working on an old Siemens PG675 and suddenly the monitor began to show a a distorted image (it shows this 1 when the should shows this 2). I could make a test of the screen, and it shows ...
-1
votes
3answers
209 views

What exactly has the windows OS relationship been towards MS server offerings?

This question is related to this one. I always was understanding that windows the OS was a companion app of sort in regards to the server offerings and that, yes you could use it for home use, but it'...

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