Questions tagged [filesystems]
Questions about algorithms and data structures for storing, organizing, and naming data in durable storage systems.
46
questions
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0answers
21 views
How to do atomic operations on systems that don't support it?
I need to sync data with WebDAV and other similar backend that do not have a concept of atomic operations. In some cases, I might need to read a file, change its content and write it back. And of ...
1
vote
2answers
117 views
How do you write a diff algorithm given limited amount of RAM?
Say you have two large files (100 TB each) and only 1 MB of RAM.
What's an efficient algorithm that will print the missing lines (diff)?
The files don't necessarily contain duplicates.
The two files ...
0
votes
0answers
21 views
What could happen if bitmap and data block not updated
Learning some exam questions, got stuck on this one, hope someone can help me out.
Assume that we have simple file system without a journal where we write
directly to bitmaps, inodes and data data ...
1
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0answers
38 views
How do I implement fixed block storage file system in database from typical file-level file system?
I've a typical parent ID based file system in database and files are physically stored on disks. What I want is to store files in blocks (4096K) of fixed size.
Chunking can be used I found, but how ...
0
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0answers
12 views
Calculate for each block, the number of bytes that can be assigned to data and to pointers to other blocks
In trying to solve the following problem:
You are presented with the first 15 blocks of a secondary storage device (disk) which has a total of 30000 KB available. The linked allocation method is ...
2
votes
2answers
43 views
What is the term for two file formats that describe the same amount of information?
I am working on file formats conversion. Some of them can be converted back and forth to others without losing any information (fields or precision of the numbers encoded), others file format do not ...
0
votes
1answer
21 views
No. of disk blocks writes required for writing the file
Assume that a file is written using write(fd, buf, K) system calls, where fd is the file descriptor, and K, the number of files to be written to the current file offset which is a multiple of the disk ...
1
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1answer
343 views
How pictures and videos are usually loaded in Memory? [closed]
Lets assume I'm talking about Jpeg and Mp4 and a general video player(not sure if different ones load it differently, if they do please tell)
So do video players (process) usually load the entire ...
2
votes
1answer
132 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/...
0
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1answer
19 views
Where are file-information like “created” or “last edited” actually stored?
I can access some information about the files ("created" or "last edited") on my PC. But where are those information actually stored?
Are they stored by the operation system? Could be possible as if ...
0
votes
1answer
86 views
what does the author mean by directory structure in operating system?
I'm reading Operating System Concepts by Avi Silberschatz(9thE), in section 11.4 File-System Mounting, the author explains the steps of filesystem mounting as follows:
The operating system is ...
2
votes
1answer
239 views
What's the directory structure on disk that keeps the information of all files?
I'm reading Operating System Concepts by Avi Silberschatz(9thE), in chapter 11 File-System Interface, when the author explains the concepts of file, he states that
The information about all files ...
1
vote
2answers
88 views
File systems and writing one
I am going through the following series of lectures on OS development .
http://www.brokenthorn.com/Resources/
In the fourth tutorial , I came across the term " OEM" parameter block that stores the ...
0
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0answers
47 views
How are files managed in a filesystem?
I have recently been interested in low level computer science (as a hobby), and I have just learned about the way a computer organizes and stores information on a hard drive. I have learned the basics ...
-1
votes
1answer
104 views
Source code for Network File System [closed]
I am doing a small project which explains how operations (file open, file write etc.) are done in client side and server side in network File system. Can anyone help me out providing its source code ...
2
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1answer
74 views
SSD vs HDD Retrieval Time
On an HDD if data is fragmented the discs need to be spun to where the next block in the file is, so how and where data is stored can make a big difference in how long it takes to retrieve the data. ...
0
votes
2answers
136 views
On what abstraction is a filesystem actually built on?
Data is read in terms of a block from a storage device(magnetic, optical, flash). Size of the block depends upon the filesystem and os. The physical device may have different units of storage like ...
0
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0answers
321 views
magnetic Disk Calculation
A magnetic disk has 1000 cylinders, 10 tracks per cylinder, 128 sectors per track, ...
1
vote
1answer
34 views
Why splitted text files is bigger than a large one with the same content?
I have this large text file that when unzipped has about 2GB.
I split this one into multiple(more than 5 million) files and now I have a folder of about 20GB, how is this possible?
2
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0answers
39 views
Importance of contiguous allocation on flash disks
All file systems I know make significant efforts to try and allocate files in contiguous blocs on a disk.
But if the disk is an SSD using flash technology underneath, is there any benefit to ...
9
votes
2answers
654 views
What is a file?
I'm looking for a formal definition of file that does not only include storage but also abstractions like procfs or /dev/null (or any fuse-based file) that do not relate to storage.
So far I know ...
1
vote
0answers
67 views
Algorithm for generating file systems
I'm working on an I/O generator program for a distributed file system. The problem I need to solve can be worded as a set of requirements:
Reproducible (i.e. given some initial condition, the ...
1
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0answers
51 views
Advantages of using a RDBMS
Apologies if this isn't the correct forum but I thought it would be too academic for the DBA forum. In my work I'm looking to research some of the benefits of using an RDBMS product over traditional ...
1
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1answer
1k views
What type of an algorithm is being used for directory structure scanning?
So after learning about DFS and BFS yesterday in my class I was curious as to how is scanning on various file system being done. I spent quite a bit of time trying to look for some references on the ...
0
votes
1answer
71 views
What happens under the hood when the process requests operating system to open a file?
Suppose a process wish to open a file named test.txt. So it issues a system call requesting Operating system to find the file on disk,and to grab the handle of file to operate on it. My question is ...
3
votes
3answers
440 views
Typical file structure
Short version
The question & answers relate to the following topics:
File as a collection of records vs. file as a stream of bytes
Sequential File
Distinction between file data and metadata
...
0
votes
1answer
21 views
How a file is determined [closed]
If I have the integer ""1234" stored in a file, the size of the file when I use the command "ls -l" or "wc -c" is 5. If I have "12345" the size of the file is 6. Basically the number of bytes in a ...
1
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0answers
217 views
retrieve file format from unknown binary file [closed]
Is it possible, somehow, maybe by using some kind of brute force algorithm, to try and figure out what kind of file one is dealing with when one only has the raw binary without file format or meta ...
-2
votes
1answer
1k views
Deleted data remains on a disk until? [closed]
I am little bit confused between the two answers below.
What is the exact answer of this question?
My query is,
"Deleted data remains on a disk until...?"
The data is overwritten;
The recycle bin is ...
0
votes
1answer
45 views
How to parse data in a text file? [closed]
I had a question about altering a text file. I have data in the following format.
1 a,b,c
2 d,e
3 a, l, m,n
Note that some of them have spaces after the coma
...
0
votes
2answers
704 views
What is the file system of ram?
As much I know about a memory and storing data there would always be a managing type feature in every memory which manages all the data and its location. So, what is the file system of a RAM. I also ...
1
vote
0answers
23 views
Coordinate Systems in Files (pixels) [closed]
I'm trying to solve the problem of transferring data from a pdf file to another file type. When extracting data from PDF files I am to use the exact coordinates (where each unit is 1/72 of an inch in ...
0
votes
0answers
296 views
What are disadvantages of a Operating System that recognise file extensions ?
When Operating system recognise the file types It has several advantages like
1. avoid mistakes like trying to print a object file that produce garbage output
but I can't think about disadvantages ...
2
votes
1answer
3k views
How is the directory implementation done using a linear list?
I am reading Operating System Concepts by Silberchatz, Galvin, Gagne and they write that a directory can be implemented using a linear list. [pg 470, 8th ed]
However, I visualize directories as a ...
2
votes
1answer
71 views
Is every file an integer amount of bytes?
I'm not sure whether I'm asking on the right site, since all the other questions seem to be a lot more abstract and theoretical. If I should remove the question, please tell me.
Are all files on my ...
0
votes
1answer
33 views
Can file snapshots aid in detecting malware?
I noticed certain programs have a feature that can have a 'snapshot' of a file from a certaim time and compare it to a more recent snapshot of the file. If one's system has a snapshot of a program ...
2
votes
2answers
6k views
B-Tree and how it is used in practice
I understand what a B-Tree is (I already implemented a B-Tree in Java with insert and delete methods that preserve the invariant).
However I do not understand exactly how it is used for example for ...
2
votes
1answer
65 views
Filing systems using index blocks
I know that a disadvantage of the index block system is that it can be wasteful of space if the files involved are mostly small in size, as index blocks are allocated from free space as required and ...
0
votes
1answer
828 views
Maximum possible file size in the filesystem [closed]
A file system with 300GByte disk uses a file descriptor with 8 direct block address ,1 indirect block address and 1 doubly indirect block address. The size of each disk block is 128 Bytes and the size ...
0
votes
1answer
26 views
How to name documents in windows? [closed]
What is the best way to name documents and folders in windows? Im thinging about maybe there will be some conflict in some programs? Or when searching in terminal
This_Is_Best.doc
ThisIsBest.doc
...
4
votes
1answer
1k 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 ...
1
vote
2answers
74 views
Random file access in a block based file format
I am writing a program to store, retrieve and delete "blocks" of data of varying sizes.
The way it currently works is by keeping a database storing the locations of the blocks and the locations of ...
2
votes
1answer
65 views
Studies of file access patterns in embedded systems
I am considering what elements an operating system for Network On Chip systems might have and the issue of file systems looms large. NoCs have an embedded heritage, and their domain of use (at least ...
5
votes
2answers
238 views
What if the electricity goes off while a file is being renamed?
Suppose I'm renaming a file and the electricity goes off right in the middle. Naively, it looks like the file could be in some “half-renamed” state. Maybe the name would have half the old name and ...
2
votes
1answer
94 views
Monitoring files in preservation archives
What are efficient and accurate techniques for monitoring the recoverability and integrity of files in very large preservation archives?
In very large archives, the time taken to recompute checksums ...
11
votes
4answers
210 views
Why store self and parent links (. and ..) in a directory entry?
Consider an filesystem targeted at some embedded devices that does little more than store files in a hierarchical directory structure. This filesystem lacks many of the operations you may be used to ...
