Questions concerning low-level aspects of a system: programming close to the underlying details and hardware.
Questions tagged [low-level]
75 questions
83
votes
7 answers
Why are bit masks called "masks" and what purpose do they serve?
Why are "bit masks" called like this?
I know that they are mainly used for bitwise operations and the usage of bit masks is more efficient than the usage of separate variables.
However my question is why and when were bit masks invented? Were they…
yoyo_fun
- 2,297
75
votes
11 answers
Why are cryptic short identifiers still so common in low-level programming?
There used to be very good reasons for keeping instruction / register names short. Those reasons no longer apply, but short cryptic names are still very common in low-level programming.
Why is this? Is it just because old habits are hard to break,…
Roman Starkov
- 4,499
60
votes
6 answers
Why do many functions that return structures in C, actually return pointers to structures?
What is the advantage of returning a pointer to a structure as opposed to returning the whole structure in the return statement of the function?
I am talking about functions like fopen and other low level functions but probably there are higher…
yoyo_fun
- 2,297
58
votes
11 answers
Were the first assemblers written in machine code?
I am reading the book The Elements of Computing Systems: Building a Modern Computer from First Principles, which contains projects encompassing the build of a computer from boolean gates all the way to high level applications (in that order). The…
The111
- 753
56
votes
4 answers
Development process used for the code on Apollo 11 missions?
The Apollo missions had technology no more complicated than a pocket calculator.
From link here, there's an information about Apollo Guidance Computer (AGC)
The on-board Apollo Guidance Computer (AGC) was about 1 cubic foot with 2K of 16-bit RAM…
Josip Ivic
- 1,657
43
votes
10 answers
Why not have a High Level Language based OS? Are Low Level Languages more efficient?
Without being presumptuous, I would like you to consider the possibility of this.
Most OS today are based on pretty low level languages (mainly C/C++)
Even the new ones such as Android uses JNI & underlying implementation is in C
In fact, (this is a…
rtindru
- 549
41
votes
5 answers
What is the absolute minimum set of instructions required to build a Turing complete processor
I have a general idea of how the processor handles instructions but spend my time working in mostly high level languages. Maybe somebody who works closer to the iron can provide some valuable insight.
Assuming that programming languages are…
Evan Plaice
- 5,785
35
votes
13 answers
Low level programming - what's in it for me?
For years I have considered digging into what I consider "low level" languages. For me this means C and assembly. However I had no time for this yet, nor has it EVER been neccessary.
Now because I don't see any neccessity arising, I feel like I…
back2dos
- 30,140
34
votes
11 answers
Is it wise for a high level developer to spend time studying assembly?
It is clear that the knowledge of low level stuff is very important in our work.
But in a situation where you're already developing commercial software on a high level, and when you already have a chosen direction but don't have any assembly skill,…
zkaje
- 443
34
votes
13 answers
How good does a well-rounded programmer need to be with bit-wise operations?
I have been browsing some OpenJDK code recently and have found some intriguing pieces of code there that has to do with bit-wise operations. I even asked a question about it on StackOverflow.
Another example that illustrates the point:
1141 …
c_maker
- 8,310
25
votes
3 answers
Why do executables depend on the OS but not on the CPU?
If I write a C program and compile it to an .exe file, the .exe file contains raw machine instructions to the CPU. (I think).
If so, how is it possible for me to run the compiled file on any computer that runs a modern version of Windows? Each…
Aviv Cohn
- 21,538
22
votes
7 answers
How do programmers deal with low level software development in high level languages?
I am somewhat new to programming and the best way I can ask this question is with an example.
I know how to do basic things in Java and C#. Things like a small windows forms application or make a generic class. I've basically been learning and…
fender1901
- 485
22
votes
9 answers
What are the complexities of memory-unmanaged programming?
Or in other words, what specific problems did automated garbage collection solve? I've never done low-level programming, so I don't know how complicated can freeing resources get.
The kind of bugs that GC addresses seem (at least to an external…
deprecated
- 3,297
17
votes
10 answers
As a programmer, should I know low and high-level programming languages?
I been contacted to do some work remote controlling LEDs displays over TCP/IP, but my experience and preparation is mostly about high-level programming language. I said that to the person who contact me about the work and he told me that:
"if you…
job
- 183
17
votes
5 answers
How to comprehend abstraction in code?
When looking at a new codebase I like to start from a bottom-up approach.
Where I comprehend one file and then move up to the next abstraction.
But often times I find myself forgetting what the lower-level abstraction is doing.
So I'll be at this…
John DeBord
- 299