What is the output of the following program considering an x86 based parameter passing sequence where stack grows towards lower memory addresses and that arguments are evaluated from right to left:
int i=10;
int f1()
{
static int i = 15;
printf("f1:%d ", i);
return i--;
}
main()
{... (2 Replies)
I want to read a large (~1-4Gb) txt file with fields separated by "," and line separator "\n". Unfortunately, file contains \x00 (zero ASCII) symbols
AWK treats them as end of line + it ignores reminder of the line after the \x00.
As a simple example:
echo "\0060\0061\000\0060\0063" | nawk... (6 Replies)
hi all, i have a flat file delimited by pipe (|), and i'm loading it to sybase, the problem is when i do a select to the table of the database, the last field has new line ascii (\x0a):
38,'0\x0a '
88,'076004074028\x0a '
27,'076004075023\x0a '
how can i remove the \x0a from... (1 Reply)
Hello All,
I have a requirement where I need to replaced the hex character - '\x0D' with 2 hex characters - 'x0D' & 'x0A'
I am trying to use SED -
But somehow its not working. Any pointers?
Also the hex character '\x0D' can occur anywhere in the line.
Can this also be accomplished... (6 Replies)
Hi, everyone:
I'm new to xen.
When I install a vm on centos5.5, I got xen crashed:
# virt-install -n centos5 -r 512 --vcpus=1 --disk path=/home/mycoy/centos5.img,size=8 --nographics -l http://mirror01.idc.hinet.net/CentOS/5.5/isos/i386/CentOS-5.5-i386-netinstall.iso
when... (1 Reply)
Perl allow hex character with just one digit.
Such as \x0 \x9 \xA.
How to force to use 2 digits in m// and s///.
Such as \x00 \x09 \x0A.
---------- Post updated at 05:20 PM ---------- Previous update was at 03:38 PM ----------
I don't know why these code replace as text, not a real hex... (0 Replies)
Discussion started by: natong
0 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)