69
votes
Accepted
What's the difference between a variable and a memory location?
A variable is a logical construct that goes to the intent of an algorithm, whereas a memory location is a physical construct that describes the operation of a computer. Generally speaking, in order ...
- 34.8k
20
votes
What's the difference between a variable and a memory location?
Is it safe to say that a variable is the same thing as a memory location?
No. Variable and memory location are two abstractions at two different abstraction levels. Variable and pointers are higher ...
- 12.5k
17
votes
What's the difference between a variable and a memory location?
Variables are language constructs. They have a name, reside within a scope, may be referenced by other parts of the code, etc. They are a logical entity. The compiler is free to implement this ...
10
votes
How did heavy software in the early days managed to run on 4MB RAM computer?
How did heavy software in the early days managed to run on 4MB RAM computer?
It wasn't heavy.
That's it. There is no magic to it. Your question is based on a false premise.
I remember that my mom ...
- 105k
10
votes
How does the Base Address Registers (BARs) in a PCI card work?
This question should be moved to stackoverflow. Maybe someone will do that.
Am I correct?
Essentially, yes.
Each BAR holds the address of a communication area. This address can be set and read by ...
- 34.8k
9
votes
Accepted
What are best practices for enterprise software, should a developer be able to login as one of its users? (when its your own company)
There is no standard which is used by every company: some rely on impersonation; others avoid it at all costs.
Impersonation was useful fifteen years ago, where there weren't many convenient tools for ...
- 139k
8
votes
Accepted
What does "data bus control" mean?
Yes. The DMA controller takes ownership of the bus for the duration of the transfer.
That said, I feel obliged to point out that at least on PC-based machines, DMA controllers have been almost ...
- 44.9k
5
votes
How did heavy software in the early days managed to run on 4MB RAM computer?
Microsoft Word for Windows was by today's standard a very small program. Its size is 13.07 MB on installer disks (1.44 MB each), which you can download to check for yourself.
Microsoft Word 6.0 for ...
- 390
5
votes
What's the difference between a variable and a memory location?
Let me focus on your actual question - "who's right?" when comparing these two statements:
A pointer is a variable whose value is the memory address of another variable
A pointer is a memory location ...
- 221k
5
votes
What's the difference between a variable and a memory location?
I certainly wouldn't say that a pointer is a memory location that contains an address. For one, I'm not aware of an architecture where 0x23453 could fit in a single byte. :) Even if you handwave ...
- 346
5
votes
Accepted
Is it possible to translate binaries from one instruction set to another?
Machine code is a language like any other language. "Translating" from one language to another language is called "compilation", and we have compilers for all sorts of source and ...
- 105k
4
votes
Accepted
Is it viable to use imprecise analog computers to simulate equally artificial intelligence?
tl;dr– They're optimizing critical functions by custom-designing computers to perform those specific tasks. It's basically about optimizing efficiency.
Right now, equilibrium propagation is only ...
- 1,101
3
votes
What's the difference between a variable and a memory location?
I know you've already accepted an answer, and this question has five answers already, but there's a point they don't mention, one that I think tripped you up. CS textbooks often try to be agnostic ...
- 1,379
3
votes
How can I alter a system design to improve computational efficiency with AWS?
There's a couple key concepts in here that will limit your ability to scale:
Monolithic design
Combinatoric set of artifacts per user
Serialized updates to database
Of those, the first two are the ...
- 46.5k
3
votes
Accepted
What strategies exist to determine the speed up a GPU will have on an algorithm?
There are some approaches supporting you for performance prediction. However, to be honest, most of them (if not all) have a slight speculative character, so prediction is not always meeting the ...
- 344
2
votes
Is there genetic relationship between ARM and PDP-11 architectures?
The two assembly languages have similarities, as mentioned previously. But their concept is different.
PDP11 was famous of its many addressing modes, which is not true for ARM. Also, PDP was ...
2
votes
is it possible to increase the offset in a jm(jump command inside)?
Your architecture doesn't have a direct path from memory to the PC - the only thing that can be done with the result of a memory read is storing it in a register.
In order to implement an indirect ...
- 17.9k
2
votes
What are the CPU architectures for the most common general purpose devices (i.e., Android, Windows/Linux PC, RaspberryPi etc.)?
From software in user space, you basically don't have to care about RAM architecture.
There are approximately two CPU lines you need to care about, Intel/AMD vs ARM, each of which comes in a 32-bit ...
- 15.3k
2
votes
What are the differences between memory coherence and cache coherence?
When you use caches, data isn't usually written to memory immediately. Consider two cores A and B with caches X and Y and memory M.
If A writes data, it will update cache X but not immediately memory ...
- 49.4k
2
votes
Accepted
Do multiple software-threads on a single hardware-thread system execute sequentially?
This is far from hypothetical:
Before multithreading CPUs, running multiple threads and processes on a single threaded CPU was a common practice, supported by many OSes.
There a still a lot of ...
- 82.3k
1
vote
Double check of Book Erratum regarding Harvard Architecture and Von Neumann architecture
But isn't it supposed to be Von Neumann architecture that shares the same memory address space regarding data memory and instruction memory?
No, the difference between Von Neumann and Harvard ...
1
vote
What are best practices for enterprise software, should a developer be able to login as one of its users? (when its your own company)
One user should never be able to be another user in production. The system should always know who the user is and accurately record who made any changes.
But that’s not the end of the story. Because ...
- 11.2k
1
vote
What are best practices for enterprise software, should a developer be able to login as one of its users? (when its your own company)
Whether you own the company or not, I think the only clean way is the ability to change someone’s password, in a way that is clearly and undeletably logged. If you can log in as an arbitrary user ...
- 49.4k
1
vote
Do multiple software-threads on a single hardware-thread system execute sequentially?
First consider that if a single core system allowed only one thread, then it would be logical that a processor with 16 cores would allow only sixteen threads - my Mac runs a few hundred right now.
...
- 49.4k
1
vote
Computer Architecture : Out of order execution - Load/Store
There is a concept of Load Store Queue (LSQ) in Computer Architecture. You always keep the instructions in the order in LSQ.
L/S
Address
Value
Commit
L
?
?
No
S
0x11
6
No
The above table is a ...
- 11
1
vote
Computer Architecture : Out of order execution - Load/Store
Out of order execution is a microarchitecture detail. The CPU may reorder instructions only when this doesn't change the observable or specified behaviour. Here, this can be achieved in one of two ...
- 136k
1
vote
What's the difference between a variable and a memory location?
The statement A pointer is a variable whose value is the memory address of another variable is oversimplified. But by the time a reader understands what exactly a memory location is, and how it ...
- 3,778
1
vote
Accepted
Distributed System or not?
Your system has a 3 tier architecture, since it has the following components:
a front-end (presentation tier)
a back-end (application tier)
a database engine (data tier)
and each component could ...
- 82.3k
1
vote
What was the first mechanical Turing-complete machine ever constructed?
There is a good chance that Jim MacArthur's machine (mentioned in the question) is in fact the first.
Here are the contenders I am aware of:
The Analytical Engine. As joeytwiddle points out, it has ...
- 113
Only top scored, non community-wiki answers of a minimum length are eligible