Hi,
I have a simple question... In C do we have a standard library function which will return the pointer to a substring at certain offset and having certain length...
Ofcourse we should take care not to access beyond allocated length in the parent string and don't overwrite beyond allocated... (2 Replies)
Hello all,
I am trying to add chunks to my informix dataspace. I have one dataspace ( the rootdbs ) and the new chunk is a raw device. Precisely slice1 on my new external harddisk.
The question is, what should be the offset value. The document says, the offset is used by the engine to... (1 Reply)
Hi,
I want to read a file from a specified offset from the start of file. With the read command, is it possible to do so. Please suggest. Is there any other alternative?
Thanks,
Saurabh (2 Replies)
Function: int fcntl(int fd, int cmd, struct flock * lock)
Data Type: struct flock
This structure is used with the fcntl function to describe a file lock. It has these members:
off_t l_start
This specifies the offset of the start of the region to which the lock applies, and... (1 Reply)
I have read the below from the book bash cookbook.Tail +1 filenames is similar to cat filename
I have tried the same in Ubuntu 11.10 with bash. 4.0 .
I have received error for the Same.
May I know in which system that will work fine ?
Thanks (1 Reply)
Hi ,
I have a .gz file whose contents look like below.
data1^filename1
data2^filename2.
..
.
.
Is it possible to find out the byte offset of each record from the .gz file.
Like in an uncompressed file.
grep -nb "Filename" give the byte offset of the record in this case.
... (4 Replies)
How can I get GMT offset from EST for a particular date(not current date) in unix. For example, user enters date as: 2012-06-25D11:49:37, this is GMT. I have to calculate GMT offset from EST in unix for this input. Thanks in advance.
-Steve (1 Reply)
Dear all,
I want to offset the file numbers. can you please make some awk code or linux code for the same.
Example:
input file names
ANI_WFMASS_PIST00001.gif
ANI_WFMASS_PIST00002.gif
.
.
.
ANI_WFMASS_PIST0000n.gif
offset --> 30
ANI_WFMASS_PIST00031.gif
ANI_WFMASS_PIST00032.gif... (14 Replies)
Discussion started by: kri321shna
14 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)