Questions tagged [programming]

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16
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1answer
1k views

What did memory dumps look like on 36-bit machines like PDP-10s?

I spend a lot of time looking at hex dumps of memory, which have a format that should be familiar to most: 00010000 00 FF 48 65 6c 6c 6f 20-77 6f 72 6c 64 21 00 00 ..Hello world!.. But on 36-bit ...
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Which is the first non-assembly (and binary) language to write operating system(s)?

Many programming languages predating C, like FORTRAN, LISP, B, BCPL, were either special purpose or too heavy to write OS. OS were bound to their hardware architecture and died with them. C was used ...
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Was the RPL language for the Commodore PET ever used other than by its author?

Note that this question is about the programming language RPL for the Commodore PET, not the HP language with the same name. RPL was developed by Tim Stryker and sold through his company Samurai ...
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When was an image of an apple first used to promote the APL language

The APL community is contemplating the adoption of a common logo but some are worried about trouble from Apple lawyers. Now, IBM and others have been using apple motifs in promoting APL for a long ...
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6answers
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How did early computers handle mice?

Early computer mice worked by sending a series of pulses; the more rapid the movement, the higher the frequency. How was this handled at the computer end? At one level, it sounds easy: just run a loop,...
7
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1answer
248 views

Are there any other historical traces of the earlier versions of the Alternate Multiplex Interrupt Specification by Ralf Brown?

I'm a fervent user of the Alternate Multiplex Interrupt Specification for 86-DOS systems, a method using a common set of multiplexer interfaces over interrupt 2Dh. It was originally developed in the ...
10
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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 ...
5
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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
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1answer
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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 ...
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0answers
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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?
16
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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 ...
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2answers
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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/...
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6answers
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Why did the monsters have "infinite invisible pillars" of hitboxes vertically in all versions of the DOOM engine?

Even in the last version of the DOOM engine, v1.9, used for Final DOOM, there is this strange limitation in which all the monsters have an invisible, infinitely tall "pillar" above and ...
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2answers
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Porting use of BASIC to-the-power ^ operator

So I was porting one of the old BASIC games from the book "BASIC Computer Games", Ref: https://github.com/coding-horror/basic-computer-games to Python, just for fun. I came across the ...
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7answers
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Why do variable names in BASIC need type suffixes?

The BASIC I'm most familiar with is Atari BASIC since I had an Atari 800 way back when. The Atari BASIC Source Book includes details about how Atari BASIC maintains variables. There is a Variable Name ...
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2answers
379 views

Flash border color during Kernal LOAD routine

I would like to use the Kernal's LOAD routine to load a file into memory, because that seems to be the easiest way to do it. However, that LOAD call is synchronous in the sense that it returns once ...
16
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3answers
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Why can't I invoke the next interrupt service by incrementing the AX register after calling the same interrupt?

I have two snippets of 8086 assembly code, both of which are supposed to do the same thing: make the mouse appear on the screen. Show_Mouse: push ax mov ax,0 ;Reset Mouse int 33h ...
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3answers
5k views

Which language had the first scanf?

As a companion to the question "What was the first programming language to have 'printf'?", which language had the first scanf? It doesn't have to be literally called scanf, but I am looking ...
5
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1answer
356 views

Why does the ‘Get Next Selector Increment Value’ DPMI call exist?

In DPMI, interrupt 0x31 services 0x0000 and 0x0100 are capable of simultaneously allocating multiple protected-mode selectors in a single call. When that happens, both services return only the first ...
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2answers
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How can I access the VGA card's ROM fonts with interrupt 10h operation 1130h in protected mode C?

I'm using Open Watcom 1.9 to write some 286 real mode, and 386 protected mode software for DOS in C. In real mode, I can retrieve a pointer to the system ROM character bitmaps in real mode using int ...
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1answer
3k views

What was the first programming language to use `+` for string concatenation?

Many reasonably modern programming languages (Java, Python, C++, Ruby) use + to represent string concatenation. "A" + "B" is the string "AB". Languages with a more ...
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2answers
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What really prevented PC games from using hardware scrolling on CGA

According to https://en.wikipedia.org/wiki/Adaptive_tile_refresh: CGA (the previous generation of PC graphics hardware) lacks features for scrolling in hardware so PC games started featuring ...
3
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1answer
228 views

Why were procedure parameter specifications optional in the ALGOL 60 Revised Report?

In Algol 60 procedure declarations, the 'specification' part was optional for by-name parameters. The specification is what gives (loosely speaking) the type of parameter - whether it's real, integer,...
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1answer
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Which extant ALGOL-60 compilers fully support numeric labels?

This question is prompted by a related one by texdr.aft. It turns out that the Revised report on Algol-60 allowed numeric labels (3.5.1, page 15), <label> ::= <identifier> | <unsigned ...
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4answers
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Why does Pascal have numeric labels?

Pascal was intended, in part, to be a simple language to implement. Some of the design decisions reflecting this are Declarations/definitions must be given in a strict order (labels, constants, types,...
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1answer
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In what year did term "program" first appear in the meaning of "series of coded instructions"?

I'm trying to figure out year when the term "program" was firstly used is the meaning ‘a series of coded instructions which directs a computer in carrying out a specific task’. Additionally ...
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5answers
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Why didn't C++ specify filename extensions?

Apparently even today there is no single "official" standard for C++ file extensions. There are just common conventions. To me this stands out as an anomaly... file extensions are heavily ...
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3answers
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What was the first programming language, other than Lisp, to have “short-circuiting” Boolean expressions?

(This question is, of course, another thrilling installment of “The history of expression evaluation”; see the previous episodes here and here.) In many programming languages, the Boolean operators ∧ ...
57
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4answers
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Why were single quotes ('…') chosen for characters, and double quotes ("…") for strings?

In C, '' is used to denote a character, while "" is used to denote a string. Why was this syntax chosen? I tried to research this using Wikipedia’s Timeline of Programming Languages along ...
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3answers
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What was the first programming language to support “operator chaining”?

The Python language has a neat feature: An expression like x < y <= z is interpreted, according to mathematical convention, as equivalent to x < y and y <= z. Operands are evaluated only ...
107
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7answers
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Why was `!` chosen for negation?

It seems that the use of the exclamation mark ! to denote negation started with the C programming language (as far as I can tell from my Google research). Nowhere though is mentioned who and why chose ...
12
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2answers
644 views

What was the first programming system to place no limitations on the length of identifiers?

Historically, interpreters and compilers have limited the length of identifiers. For example, FORTRAN I and II considered only six characters to be significant, and LISP 1.5 forbid symbol names to ...
14
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2answers
829 views

How much of the Program Segment Prefix area can be reused by programs with impunity?

I am writing a tiny TSR program, and I want it to take as little memory while installed as possible. The memory footprint of every loaded DOS process, including a TSR, includes a data structure known ...
9
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1answer
632 views

What was the first compiler/interpreter/assembler to indicate problematic columns in diagnostic messages?

These days, most compilers and interpreters seem to provide the following in diagnostics: A description of the problem The name of the source file A line number A relevant position within the line ...
13
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6answers
670 views

Are there any primary sources for the “passing constant by reference” behavior in old Fortran compilers?

Occasionally I have heard references to a peculiarity of certain (old) Fortran compilers, with regards to subprogram argument passing. Here is an example, from an answer to a Stack Overflow question: ...
2
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3answers
604 views

M68k Big Endian to Little Endian

I'm trying to write a binary file using vasm68k_mot (Motorola 68k) writing File-Size and File-Offset everything goes well, except that M68K is Big-Endian, there's a way I can change to Little-Endian ...
3
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1answer
243 views

Python2.4 Amiga OS M68K restarting system and where to get libs

Just installed python 2.4 on my Amiga os3.9. sometimes when I run a script the machine restarts. Any idea why that may be? It has 030 with MMU, 64MB RAM and 1MB chip ram. All MMU libs are installed. ...
4
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1answer
176 views

How were card sequence numbers typically checked?

Although average punched cards had eighty columns, often only seventy-two were used for characters; the remaining eight were ignored by software. Hence arbitrary metadata could be included with each ...
7
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1answer
204 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 ...
27
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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 ...
14
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1answer
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Who are the people associated with Simula, Assembler and Fortran in this video?

I am watching a recording of a discussion panel ‘Unix50 - Unix Today and Tomorrow’, part of which contains Bjarne Stroustrup’s talk ‘From C to C++’, discussing the history of C++. At 20:46 there is a ...
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3answers
777 views

Was there anything about the "power of the NES" that made Super Mario Bros. have "realistic physics"?

If you look at older platformers, and even many later ones for other platforms and even the NES, there is typically no "momentum" and "realistic" physics for the main character ...
4
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2answers
421 views

Are ECMA and ANSI sister organisations?

ECMA was the body that formalized JavaScript while ANSI was as I understand it the body that formalized much of the early C programming language, what became known as ANSI C. Are these two ...
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3answers
572 views

Uh, oh, I've woken up in 1973. Can I get a job in computing? [closed]

I've woken up in 1973. Until I can figure out how to monetize my knowledge of coming political, economic, and social trends, I need to support myself somehow. So... I walk into one of the major ...
5
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1answer
215 views

Multi-GPU PowerMac G5?

I’ve got a 2005 PowerMac G5, Dual 2.3 GHz with a stock Nvidia GeForce 6600 running OSX 10.4 Tiger that I enjoy experimenting with, purely for fun and to learn writing legacy software in XCode. Would ...
21
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1answer
2k views

Where are the sources of the original curses library?

The curses library is a terminal control library for Unix-like systems used in text based user interface applications. It has been used in many games in the past. It was developed by Ken Arnold and ...
6
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1answer
183 views

Chaining IRQ's with BASIC & Kernal routines turned off

Having disabled BASIC and Kernal routines I set up an IRQ to run the following code when the raster line reaches 200: .irq1 inc 53280 // change border colour // lda #$ff // clear the ...
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4answers
744 views

Are there some non-OOP programming languages that does not allow you to make a variable private? [closed]

In the non-OOP programming languages that I know of, you can't make a variable private (i.e. there is no private keyword), but there are some tricks that you can use to effectively make a variable ...
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13answers
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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 ...
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3answers
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When was the phrase "sufficiently smart compiler" first used?

In discussions and arguments about programming language design, one often hears comments about "sufficiently smart" compilers, as in "X needn't be inefficient, since a sufficiently ...