Does anyone out there know of ANY specific books pertaining to SGI's flavor of Unix - IRIX?
I have been in contact with SGI directly and they have not supplied me with any usable reference material or manuals.
I realize man pages are a good source for info, but I need to go a little deeper... (6 Replies)
Using bash, I'm trying to read a .properties file (name=value pairs), assigning an indirect variable reference for each line in the file.
The trick is that a property's value string may contain the name of a property that occurred earlier in the file, and I want the name of the 1st property to... (5 Replies)
I'm looking at http://www.opengroup.org/pubs/online/7908799/xsh/pthread.h.html trying to understand mutexs and semaphores. Windows makes a distinction between the two. Is a mutex and semaphore different in unix land?
Is there a tutorial on threading in unix somewhere?
I'm also looking at... (4 Replies)
hi there
I have the following script in which i have created a PrintHash() function.
I want to pass to this function the reference to a hash (in the final code i will be passing different hashes to this print function hence the need for a function). I am getting an error
Type of arg 1 to... (1 Reply)
This log file is wacky.
the syntax puts this in the Installation line:
Installation PATCH75682.91 of PATCH75681 complete
Installation PATCH76537.91 of PATCH76537 complete
Installation PATCH92217.91 of PATCH92217 complete
So I'm looking for a sed 's///' to remove the first PATCHxxxx... (6 Replies)
Hi All
I have a doubt and want to be cleared I am using
@array = (10, 20);
$rarray = \@array;
#print "$rarray\n";
#print "@$rarray\n";
$rr= \$array;
#print $$rr;
$rr++;
print $$rr;
As you can see the $rr contains the reference to the first element of the array , now as the... (5 Replies)
Hi all,
I am new and I am very interested in Awk programming language and would like to know what references or books that really worked for you that was clear, concise with simple examples.
much appreciated in advance. (1 Reply)
I have the following entries and want to perform a sort.
Each entry is separated by a newline, however each line should not be considired seperate. Maybe an awk program or similar, or a small script.
Anderson, E.R., Duvall, T.L., Jr., and Jefferies, S.M., 1990. Modelling
of Solar... (6 Replies)
Discussion started by: kristinu
6 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)