Need programmer to work on 8-12 month project near Dallas, Texas or can telecommute to make changes to SCO File Pro 32 UNIX software that was converted to DOS.....Can't find anything as good as what we had in any other OS. Brent Davis brentd@texasspecialty.com (0 Replies)
here is a code which sends and receives sms through a serial port. the problem is that its givin segmentation fault. it first sets the file discriptor and the initialises the modem by using AT commands. there are two threads for reading and writing . rest the code is simple you'll get it. user has... (1 Reply)
Prompt please where the error occurred.
text.txt obtained by ls-lah> text.txt
proc file_to_mas {name_file} {
set fileid
seek $fileid 0 start
global mas
set mas(0) 1
for {set i 0} {!} {incr i} {
gets... (2 Replies)
Hi all
I am application Programmer.
In my college(2 yrs back) i have learnt Unix i.e commads, shell scripts, Filesystem,I reffered to a book by "Sumitabha Das".
I want to learn Linux.
But i cant understand where should i start from and which book to refer to.
Most of the books these days eg.... (2 Replies)
I am trying to practice to create Makefiles. The goal is to create a makefile such that if a change is made to any of the source code files, the project can be rebuilt by typing make at the command line.
I have the following files:
ac.cc: has include ac.h and pg.h
fr.cc: has main... (8 Replies)
e.g.
File name: File.txt
cat File.txt
Result:
#INBOUND_QUEUE=FAQ1
INBOUND_QUEUE=FAQ2
I want to get the value for one which is not commented out.
Thanks, (3 Replies)
Discussion started by: Tanu
3 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)