hi I am vijay
how r the unix gurus?
I want to install unix for our sites.So pls tell me abt unix installation user guide & also all the unix commands.Pls help me.I am waiting for yr reply.
bye..........vijay :D (2 Replies)
HI Friends,
I wanted to start this thread inorder to keep all the Unix starters to easily find useful material through this thread...I request you all to provide with the URL address of any gud material you know...
thanks and regards... (2 Replies)
Hi, I need some help with the follow questions :(. Any help would be great!
Answer with the necessary commands
1. In your login directory, make a directory called week4/revision
2. Without changing directories, make another directory week4_revision/data
3. Change to week4_revision/data... (2 Replies)
Hi,
I want to prepare and then appear for Unix admin certification. Please guide me for the study material and Exams that are required to be taken for UNIX certifcation.
Thanks in advance. (11 Replies)
Hi..
I am a new joinee to this foram.I need to submit a case study in UNIX .Please help me to submit the case study by giving your valuable ideas.It will be very helpful for me.
Topic: Unix File Management
A university wants to computerize its Library operations because of... (2 Replies)
Hi all,
I hope you are fine,
I'd like study Os I tried a book like Silberschatz it's a good book but like
other books it talks about the concepts abstractly and that's due to it try
to encompass many concepts from many operating systems in GENERAL.
i am not too much comfortable from these... (20 Replies)
Discussion started by: Abdo_8008
20 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)