Most Popular
1500 questions
31
votes
5 answers
What were the differences in floppy disk formats between Amiga and IBM/PC compatible computers?
The capacity in Amiga Old File System format (OFS, OS version 1.x) was 840KB, with the Fast File System ("FFS" (!)) introduced for OS 2.x onwards able to store 880KB. The PC format stored 720KB on the same density disks.
Amigas had the same 3.5"…
nsandersen
- 1,753
- 12
- 27
31
votes
2 answers
What is the Commodore 64C "France version" and why does it need a beefy resistor?
While perusing the schematics for the Commodore 64C (titled COMMODORE-64 B/NE) I came across a suspicious section of the power supply: The unregulated "9V" is connected to the completely separate +5V with a 20 Ohm resistor, annotated with the…
pipe
- 1,718
- 17
- 20
31
votes
3 answers
Why do some people say PHP was "Pretty Home Page"? Was it once PHP's real name?
"Pretty Home Page" is not found in official PHP history. But I saw several people call PHP that way on the internet, and even in some books, teaching & publications:
An Experimental Study of Detecting and Correlating Different Intrusions | SANS…
DungSaga
- 561
- 1
- 4
- 10
31
votes
13 answers
In what language(s) is the return value set by assigning to the function’s name?
In this Stack Overflow question the original code made the mistake of using the function name as a variable, and assigned the return value to it. A commenter mentioned that he once used a language where this was the way you returned the value from…
Barmar
- 1,920
- 13
- 18
31
votes
5 answers
What really is a sound card driver in MS-DOS?
To my knowledge, neither MS-DOS nor BIOS offers any kind of API for sound cards. Therefore the concept of a "driver" is absent, as we know it today. Apart from accessories and sample files and Windows-related stuff found in the setup package, what…
Dercsár
- 685
- 5
- 13
31
votes
3 answers
Why is the ‘auto’ storage class specifier included in C?
The auto keyword in C seems quite redundant: wherever it makes sense to define a variable with automatic storage duration, it is already the default, so there is no reason to use the keyword. The keyword is so useless that C++11 managed to repurpose…
user3840170
- 23,072
- 4
- 91
- 150
31
votes
4 answers
Why did MacOS Classic choose the colon as a path separator?
I mean, all other OSs that I know of use some form of slash as a path separator, so why did Apple choose the colon?
gjvnq
- 413
- 4
- 5
31
votes
6 answers
Can I image Amiga floppy disks on a modern computer?
Is there any way of reading Amiga floppy disks to a PC hard drive? Can I use a standard floppy drive with a firmware program that will translate it? Do I need an external drive or a working Amiga computer?
wizzwizz2
- 623
- 1
- 5
- 10
31
votes
8 answers
Why did post-8008 CPUs not keep the on-chip stack idea?
Ken Shirriff writes in his blog entry about the 8008:
The 8008's seven registers are in the upper right. In the lower right is the address stack, which consists of eight 14-bit address words. Unlike most processors, the 8008's call stack is stored…
rwallace
- 60,953
- 17
- 229
- 552
31
votes
3 answers
What is DRAM refresh and why is the weird Apple II video memory layout affected by it?
I've roughly known the concept for years, but never really understood it. Back in the day, two types of RAM typically used in home computers: static and dynamic RAM. Static RAM (SRAM) was apparently easier to use because it didn't require refreshing…
bjb
- 16,259
- 46
- 141
31
votes
3 answers
How did Elite do vertex transformation?
In 3D graphics, vertex transformation is the process of converting x,y,z coordinates in 3D space, to x,y coordinates on the screen. According to https://www.khronos.org/opengl/wiki/Vertex_Transformation it is done by matrix multiplication.
That…
rwallace
- 60,953
- 17
- 229
- 552
31
votes
3 answers
Why didn't the 6502 have increment/decrement opcodes for A?
In 6502 Assembly, we can use INX and INY to increase the value stored in X and Y. They can be decreased with DEX and DEY. However, it seems that there are no such instructions for A, like INA or DEA. There is however an instruction to increment and…
LuNa
- 588
- 6
- 9
31
votes
2 answers
What is a subpixel in Super Mario Bros, and how does it relate to wall clipping?
What are "subpixels" in Super Mario Bros on the NES? How does it relate to wall clipping?
At 4:42 in the following video, the notion is mentioned in the context of how it relates to "wall clipping":
https://youtu.be/4CgC2g43smA?t=282
My own…
AlphaCentauri
- 1,533
- 1
- 11
- 22
30
votes
7 answers
Why didn't PostScript eliminate the need for printer drivers?
In the days of dot matrix printers connected by RS-232 or the IBM/Centronics parallel port, each with its own quirky set of commands, it's obvious why printer drivers were a necessary and important invention: they save every program from needing its…
rwallace
- 60,953
- 17
- 229
- 552
30
votes
3 answers
386SX, NES and how much did data lines really cost anyway?
In 1988, Intel introduced the 80386SX, most often referred to as the 386SX, a cut-down version of the 80386 with a 16-bit data bus mainly intended for lower-cost PCs aimed at the home, educational, and small-business markets, while the 386DX would…
rwallace
- 60,953
- 17
- 229
- 552