Questions tagged [storage]
The storage tag has no usage guidance.
65
questions
42
votes
9
answers
12k
views
Understanding serialization
I am a software engineer and after a discussion with some colleagues, I realized I do not have a good grasp of the concept serialization. As I understand, serialization is the process of converting ...
- 523
16
votes
8
answers
6k
views
Why we still need Short Term Memory if Long Term Memory can save temporary data?
If RAM is a short term memory and SSD is a long term memory, why don't microarchitecture of computer nowadays use SSD or another long term memory for saving temporary data like hidden variable for ...
8
votes
4
answers
9k
views
Is the 2nd parity bit in RAID 6 a simple calculation?
I'm trying to understand how the 2nd parity bit or byte is set in RAID 6. I'm reading a paper by H. Peter Anvin, and it goes into Galois field algebra, which is somewhat new to me. Anyway, a rep from ...
- 465
8
votes
0
answers
84
views
Distributed Storage for Access and Preservation
My organization wants to maintain multiple copies of data in order to preserve access in the case of localized disasters as well as for the purpose of long term preservation. Are there accepted formal ...
- 585
7
votes
3
answers
775
views
What is the minimum required storage for a sparse, depth-first octree?
For a numerical simulation framework, I use a hierarchical Cartesian grid in 3D to discretize the computational domain. I am thus looking for the most space-efficient way to store the resulting octree ...
5
votes
4
answers
459
views
A "triangular" data structure for commutative relationships
A multiplication table is symmetric over a diagonal, so only about $n^2/2$ of the elements in an $n \times n$ multiplication table contain unique information. Same goes for addition tables. In fact, ...
- 153
5
votes
2
answers
2k
views
What course in CS deals with the study of RAM, CPU, Storage?
I watched the Crash Course playlist of Computer Science. It was teaching about RAM, CPU, Storage etc but I felt it was way too fast and only people who have studied the course first hand understood it ...
- 59
5
votes
3
answers
3k
views
Does the performance of matrix multiplication depend on the storage of the array?
Two matrices can be stored in either row major or column major order in contiguous memory. Does the time complexity of computing their multiplication vary depending on the storage scheme? That is, I ...
- 163
5
votes
1
answer
2k
views
Why does RAID-5 require an additional disk for parity blocks?
I know that RAID-5 consists of block-level striping across multiple disks, but using an additional parity-check block on each disk .. and that at least two disks are required for striping.
And it's ...
- 421
5
votes
1
answer
533
views
Could a standardized ternary system be more efficient than the binary system? [duplicate]
Could a standardized ternary (base-3) system be more efficient than the binary (base-2) system? Binary is efficient for processing using logic gates, but can be bulky when using for file storage or ...
- 53
4
votes
1
answer
3k
views
Why do some filesystems have fragmentation and others don't?
I try to understand why fragmentation is a problem for NTFS and FAT but not when using inodes.
In all cases, files are not necessarily stored in a contiguous fashion so I don't see the problem for the ...
- 131
4
votes
0
answers
64
views
Extending the causal memory model to wide-area distributed storage systems
In the seminal paper "Causal memory: definitions, implementations, and programming", distributed causal memory is defined to ensures that all the processes in a system agree on the relative ordering ...
- 9,501
3
votes
4
answers
2k
views
time efficient key value store for fast lookup
Let's state a collection of key/values.
Key is an unsigned integer (0 - 2^32-1). Hense there are comparable.
Value is few bytes fixed size.
There are 4M items in the collection.
Keys are not evenly ...
- 131
3
votes
1
answer
168
views
Is there a name for "density" of information?
If we compare multimedia and text, if we have n bytes of text and compare it with n bytes of video, then we would be likely to think that n bytes of text is "more" information than n bytes of video ...
- 1,006
3
votes
1
answer
72
views
A doubt on best media for a time capsule
So, I have some data to a time capsule project of mine. But the thing is, I need to know the best media on long-time scale to use as storage unity. The time range is 120 years. Now, I've been thinking ...
- 141
3
votes
0
answers
54
views
What data structure should I use for storing my data?
I am currently looking for a way in which I can store my data, and quickly look it up.
What currently seem to be the best idea is to use a hash map.
reasons:
To identify what item I am looking for, ...
- 131
3
votes
0
answers
151
views
Representing Computations on Transcendental Numbers
Consider the set of transcendental numbers that are not compressible to a finite base-2 representation. How can I compute multiples (more generally, any algebraic computation) of one of these numbers,...
- 161
2
votes
1
answer
6k
views
SSTF disk scheduling algorithm? What if lowest seek times are equal in either direction?
Using the Shortest-Seek-Time-First (SSTF) disk scheduling algorithm (where we select a request with a minimum seek time from the current head position), what happens if the requests in both directions ...
- 173
2
votes
2
answers
4k
views
Is ROM primary memory or secondary memory?
According to this picture ROM is classified under Main Memory , but isn’t ROM a secondary storage because it’s external and non volatile ?
Any clarification with reference links will be highly ...
- 21
2
votes
1
answer
148
views
Using B+Tree to implement index, when the index-key size and the data-block size are of the same order
I want to implement an Index using a B+Tree as the underlying data structure. The index will have to support key sizes which are of order of my block size, what means I cannot save all the key as a ...
- 249
2
votes
1
answer
1k
views
Calculate storage requirements for a data set
I have a simple problem. I can't seem to even find the right search terms to get me pointed in the direction I need to be heading.
I'm writing a bunch of integers to disk. Lot's of them.
Starting ...
- 21
2
votes
1
answer
64
views
Course teaching time complexities in real life systems
Having mis-read What course in CS deals with the study of RAM, CPU, Storage? I now wonder what course in CS deals with time and space complexities including GPUs, CPU caches in multiple levels, seek ...
- 121
2
votes
1
answer
523
views
Page cache and its relationship to page table
I was reading about the page cache Page cache - the cache in memory for files, but I couldn't find the answer to my question. Does the page table have anything to do with, or maintain any entries, for ...
- 123
2
votes
0
answers
38
views
Primary File Organization in DBMS - Files of ordered records (sorted files)
"Fundamental of Database Systems", 3rd ed. by Elmasri and Navathe, page 136 says:
"We can physically order the records of a file on disk based on the values of one of their fields [...]&...
- 21
2
votes
0
answers
184
views
Regarding Amdahl's balanced system law
One of the paper titled "Rules of Thumb in Data Engineering" (Jim Gray et. el.) mentions some calculations based on Amdahl's balanced system law.
Link to paper: https://www.microsoft.com/en-us/...
- 21
2
votes
0
answers
51
views
Can you read a file as a binary number?
This is a pretty naive question, but I would like to better understand the basics of information storage on a computer. I am not concerned with the detail of how any one operating system achieves ...
- 121
2
votes
4
answers
7k
views
Difference between Sequential ,Direct and Random acess with their acess time
I'm stuck on a point while reading about these different accessing methods. As per author.
Sequential access
Memory is organized into units of data, called records.Access must be made in a ...
- 121
2
votes
1
answer
595
views
What exactly is a "binary file"?
I suspect this may be more of a concept / theory question, but, I haven't been able to wrap my brain around what exactly a binary file is.
I've read links such as the below:
https://en.wikipedia.org/...
- 21
1
vote
2
answers
117
views
Why don't hard drives actually delete data?
As far as I understand it, when you delete a file from trash/recycle bin the file isn't actually erased from memory but is instead marked as being okay to be over written.
So, my question is as to ...
- 21
1
vote
1
answer
55
views
Why did the concept of "write-protecting" not carry over from floppy disks to USB memsticks and especially external USB HDDs? [closed]
Many times, I've wished to plug in my backup hard disks into my PC without the risk of any of the data being deleted, overwritten, or modified in any manner. Purely for "inspection" and ...
- 11
1
vote
1
answer
985
views
Processes and Segmentation
The following problem was on my final and in Gate 2006, but I don't understand how to solve it:
Different methods of memory management have different overheads:
...
- 19
1
vote
1
answer
700
views
How are the number of bytes less than the number of pixels in an image?
Lets take, for example this jpeg image here
The image there is 400 x 300, or 120000 pixels and The file size of the image (on my computer) is shown to be 65171 bytes.
This means the computer stores ...
- 23
1
vote
2
answers
101
views
How can I write 2^65 on my 64-bit computer?
This is possibly a very trivial question for this site.
If I have a 64-bit laptop that means 2^64 combinations in total are possible.
But I can even get $2^{(x>>>64)}$ on my laptop.
Now, it ...
- 113
1
vote
1
answer
62
views
Why is data stored on a flash disk irretrievable if the memory chip is cracked? [closed]
All data recovery companies, regardless of skill, unanimously say that if the memory chip of a device has just a hair line crack, data recovery is impossible. Not unlikely, not expensive, but ...
- 119
1
vote
2
answers
77k
views
What is the difference between storage media and storage devices [closed]
I am having a rather distressing confusion about whether storage media and storage devices are the same terms. I found on this ...
- 641
1
vote
1
answer
43
views
Is reading contiguous pages (let's say 4KB) any faster than reading non-contiguous pages on SSDs?
I'm working my way on a problem which requires me to store elements in fixed 4KB-sized pages on an SSD. Each page is requested once for some computation on its elements, and then the CPU requests for ...
- 113
1
vote
1
answer
44
views
Fair assignment of storage for multiple writers (load balance)
I'm trying to optimize a system with a better algorithm for allocating storage. The system has 'N' writer processes and 'M' disks. (N < 30, M < 10. N can change, M is constant).
Any process can ...
- 111
1
vote
1
answer
209
views
How can I formalize key value stores with set theory?
I'm currently developing a simple key-value NoSQL store and want to build its formal model. I found article about key value formalisation with category theory, but I'm interested are there some works ...
1
vote
0
answers
31
views
Does Nand Flash Type Affect the Read Latency Based on Page Content?
In general, we have these types of NAND flash cells: SLC, MLC, TLC, and QLC. Since MLC flash cells can store 2 bits, the content of the cell can be 00, 01, 10, or 11 which are detected using different ...
1
vote
0
answers
22
views
Why do we need volume as an abstraction on top of partition?
I'm curious about what do we need volume as an abstraction on top of hardware partition? What problem it tries to solve? What is the limitation of this concept?
- 196
1
vote
0
answers
34
views
How extended logical blocks are mapped to physical device pages?
I'm reading "Decibel: Isolation and Sharing in Disaggregated Rack-Scale Storage" (PDF). On page 6, the author illustrates the concept of "Extended Logical Block"), which is similar to "Data Integrity ...
- 205
1
vote
0
answers
606
views
How to calculate multibit trie storage size?
I wish to use a multi-bit trie structure for storing IPv4 forwarding information with a fixed stride width of 8 bits, I think this is also called a "radix of 8" (so for any IP prefix 4 levels will ...
- 111
0
votes
1
answer
81
views
How can computers tell where the beginning and end of file/packet/frame headers are?
I'd like to know how a computer can determine the beginning and end of certain file components (attributes, headers, frame/packet/segment headers etc.) when these components can be omitted or added in ...
- 101
0
votes
1
answer
39
views
Confusion with Hard Disk structure
Studying Os development I encountered the need to interface with the Hard Disk Drive and thus i started learning how it actually works.
One of the problems that i found studying was that different ...
0
votes
1
answer
1k
views
How is the data stored in AVL tree in a memory? [duplicate]
I have been struggling to visualize how is the AVL tree is stored in memory?
Does it store data in array or list, If so how is it connected with its child and parents.
- 15
0
votes
1
answer
253
views
Most Efficient Way to List All $n$-bit Permutations
Suppose we are tasked with expressing a randomized list of all numbers up to but excluding $2^n$ (ie. a random list of all n-bit numbers). What are some efficient ways to do such a listing using as ...
- 103
0
votes
1
answer
1k
views
Why do computers use binary, instead of ternary, or some other logic system? [duplicate]
In binary a unit (bit), can store 2 separate values.
if you have ternary, then a unit can store 3 separate values.
why then don't computers use higher bases, for example in ternary you could have 3 ...
- 11
0
votes
1
answer
223
views
How to store factorials? [closed]
Can someone help me to store the factorial of large numbers such as 100! efficiently?
UPDATE: obviously, storing the argument rather than the factorial digits themselves achieves a significant saving....
- 113
0
votes
1
answer
39
views
Creating a numbered list, divided into types, without need for shifting or re-ordering - is this a re-occuring problem
My question is not for a solution to the problem, though I do need to put thought into it but rather my question is if this conceptual problem has a name or has been addressed at already in computer ...
0
votes
2
answers
372
views
how does a harddisk work? block / sector [closed]
Can someone explain me the way harddisks work? :/
The size of a block is specified in the filesystem, am I right? As you can see in the picture from wikipedia, the disk is divided into circle sectors. ...
