693 reputation
210
bio website
location Arlington, MA
age 53
visits member for 2 years, 3 months
seen yesterday

I've been in the computer industry since about 1979 (I had a summer programming job after graduating from high school), and I've done a little bit of everything. I've programmed in ancient languages (BASIC, PL/I, COBOL, Lisp) and more recent ones (Perl, PHP, Javascript), with a few random assemblers thrown into the mix. I've been a system programmer, system administrator, tech support engineer, and performance engineer.

I'm currently working as a programmer for Bridge Base Online, the leading online site for playing bridge. I've been learning modern web application development in the process.

P.S. My name is barmar, not barman.


Nov
12
comment Can dd copy raw data from hard drives when operating system cannot recognize file system of partitions of hard disks?
When you access the raw device, you're bypassing the filesystem driver and reading the data directly from the disk.
Nov
11
comment SSH Multiple Session -> “stdin: is not a tty”
The error message may be coming from something in your .profile or .bashrc. Put set -x at the beginning, and see where it's happening.
Nov
11
answered RIP V2 multicasting looks as broadcasting at IP add 224.0.0.9
Nov
7
comment Remove leading null blocks from a sparse file
I didn't think you were worried too much about a small run of nulls at the beginning; the important thing is not to seek past the run of nulls. I didn't notice the - 1 in the calculations.
Nov
7
comment Remove leading null blocks from a sparse file
Yeah, you just have to round down to a multiple of the block size.
Nov
6
comment Remove leading null blocks from a sparse file
There was a proposal a number of years ago for an API to make finding holes in sparse files easier: lwn.net/Articles/260795
Nov
6
comment Remove leading null blocks from a sparse file
Perhaps you should look at the source code of cp, to see how it detects sparse files
Nov
6
comment Remove leading null blocks from a sparse file
And both 1M and 2M say 16 blocks.
Nov
6
comment Remove leading null blocks from a sparse file
This seems to be more complicated than I thought. stat %b sparse.txt is reporting 32 blocks for the 8.1GB file. I think it must be including indirect blocks. If I create a file with 16K or 32K nulls at the beginning, they both say 8 blocks.
Nov
6
comment Remove leading null blocks from a sparse file
What you could do is figure out the number of null blocks there are by comparing the file's disk space with its length. Then use dd with the seek=n option to skip over the null blocks. This uses lseek, so it doesn't need to read the virtual blocks.
Nov
6
comment Remove leading null blocks from a sparse file
I've never heard of a program that modifies a file by messing with the inodes. There's no system call for doing this, it would have to be done by modifying the raw disk, and this would only be safe if you unmounted the filesystem first.
Nov
6
comment Mac OS X Disk Utility doent get my external drives ready for removal
Once you've ejected it, it's ready for removal. Not all drives spin down immediately when they're ejected. You don't need to use Disk Utility for this, you can just use the Finder Eject command.
Nov
6
comment Postfix SMTP message being marked as SPAM by Gmail and Yahoo
Your email has no Subject header.
Nov
2
comment No “$” or “#” Sign After Logging in Solaris 10 with Putty
That sounds like you're having disk errors.
Nov
2
comment No “$” or “#” Sign After Logging in Solaris 10 with Putty
Put set -x at the beginning of /etc/profile and ~/.profile. This will make them show all the commands as they're executing, and you can see where it hangs.
Nov
2
comment No “$” or “#” Sign After Logging in Solaris 10 with Putty
Does this only happen when you login using SSH, or also when you login on the console? It sounds like a problem with one of your shell startup scripts. If it happens to multiple accounts, it maybe /etc/profile or /etc/bashrc.
Nov
2
comment No “$” or “#” Sign After Logging in Solaris 10 with Putty
@choroba He posted on SO, was told that it was the wrong place, so he reposted here. What's your point? I guess he should have deleted the original, too.
Oct
31
comment Creation of 1.3 GB file takes only 1 second. How?
Try running the Sync command mentioned here after creating the ISO, see how long it takes.
Oct
30
comment Robocopy equivalent in Linux that supports Multi-threading
Google rsync multiple threads to find other options.
Oct
30
comment Robocopy equivalent in Linux that supports Multi-threading
wiki.ncsa.illinois.edu/display/~wglick/Parallel+Rsync