I work in a computer company which sells computer configurations and parts of them. And I want to give a choice to customers. If they want to buy a PC with Linux installed, not Windows. But I find difficult to test the Graphic Cards in Linux OS. I have searched the web and I didn't found any... (2 Replies)
Windows blows. I'm poor so unix is looking like a great alterative (expecially after my former roommate showed me most of the things it can do). Right now I'm looking at Debian or some other Unix kernel that would run nicley on my computer.
But the problem we had with installing it while he was... (3 Replies)
Discussion started by: beardsman
3 Replies
5. Forum Support Area for Unregistered Users & Account Problems
How to post a new thread (Regarding Unix related doubts) in Unix Forums.
I registered my id but I am unable to post my Questions to Forum.
Thanks & Regards,
indusri (1 Reply)
Hi,
I have a simulation program which creates two threads and I would like to know if I can measure the time of each individual thread. Threads communicate (I use pthread to manage them) and I want to measure communication time. I found a solution with clock_gettime and CLOCK_THREAD_CPUTIME_ID... (32 Replies)
Hi
For our load testing , we are using stubs (unix shell script) which send the response to the request coming from the application. As the unix stub is single threaded , it is responding to only one request whereas multiple requests come in parallely.
I haven't worked on thread concepts... (5 Replies)
Assume that 100 file's of type .txt are saved in directory
in which,
40 .txt files having ID 225 in column x
10 .txt files having ID 220 in column x
30 .txt files having ID 115 in column x
and remaining 20 .txt file's having UNIQUE ID say 226,227,228,229,230....first I want to read only files... (8 Replies)
Discussion started by: Akshay Hegde
8 Replies
LEARN ABOUT DEBIAN
bup-margin
bup-margin(1) General Commands Manual bup-margin(1)NAME
bup-margin - figure out your deduplication safety margin
SYNOPSIS
bup margin [options...]
DESCRIPTION
bup margin iterates through all objects in your bup repository, calculating the largest number of prefix bits shared between any two
entries. This number, n, identifies the longest subset of SHA-1 you could use and still encounter a collision between your object ids.
For example, one system that was tested had a collection of 11 million objects (70 GB), and bup margin returned 45. That means a 46-bit
hash would be sufficient to avoid all collisions among that set of objects; each object in that repository could be uniquely identified by
its first 46 bits.
The number of bits needed seems to increase by about 1 or 2 for every doubling of the number of objects. Since SHA-1 hashes have 160 bits,
that leaves 115 bits of margin. Of course, because SHA-1 hashes are essentially random, it's theoretically possible to use many more bits
with far fewer objects.
If you're paranoid about the possibility of SHA-1 collisions, you can monitor your repository by running bup margin occasionally to see if
you're getting dangerously close to 160 bits.
OPTIONS --predict
Guess the offset into each index file where a particular object will appear, and report the maximum deviation of the correct answer
from the guess. This is potentially useful for tuning an interpolation search algorithm.
--ignore-midx
don't use .midx files, use only .idx files. This is only really useful when used with --predict.
EXAMPLE
$ bup margin
Reading indexes: 100.00% (1612581/1612581), done.
40
40 matching prefix bits
1.94 bits per doubling
120 bits (61.86 doublings) remaining
4.19338e+18 times larger is possible
Everyone on earth could have 625878182 data sets
like yours, all in one repository, and we would
expect 1 object collision.
$ bup margin --predict
PackIdxList: using 1 index.
Reading indexes: 100.00% (1612581/1612581), done.
915 of 1612581 (0.057%)
SEE ALSO bup-midx(1), bup-save(1)BUP
Part of the bup(1) suite.
AUTHORS
Avery Pennarun <apenwarr@gmail.com>.
Bup unknown-bup-margin(1)