What is going on here?!
Hi,
I am trying to measure the speed of reading a given block size using the dd command.
Hi,
I went to a computer store and the salesman sold me a SATA cable and told me that all SATA cables are the same. Another salesman at a different store told me a cable rated for SATA 2, which I bought, MIGHT work as well as one rate for SATA 3 but it is not guaranteed. I decided to run a speed test on my SSD drive to check the results.
Did you perhaps run into the problem described on this page?https://wiki.archlinux.org/index.php/Pa … ning_toolsIt says:Note: The first partition created by cfdisk starts at sector 63, instead of the usual 2048. This will cause problems with grub2. grub-legacy and syslinux should work fine.
cmlr
https://bbs.archlinux.org/profile.php?id=10565
2012-07-28T00:54:39Z
I did a bunch of Googling, and couldn't find anything -- my apologies if this is answered somewhere else.
I just did a fresh install (12.04 LTS) on a new box with a Samsung SSD. I do have AHCI enabled, etc. -- all of the tips I can find anywhere else. My read speed is great. But my write speed is unbearably slow.
Code:
kevin@orangebox:~$ dd if=/dev/dvd of=~/Videos/backup.iso bs=2048 count=4169919
dd: reading `/dev/dvd': Input/output error
191160+0 records in
191160+0 records out
I'm trying to approximate the computer's write speed using dd:
dd if=/dev/urandom of=/dev/null bs=1K count=10000
which gives the following output
10000+0 records in
10000+0 records out
10240000 bytes (10 MB) copied, 0.746313 s, 13.7 MB/s
How can I get the '13.7 MB/s' into a bash variable?
The following static allocation gives segmentation fault
double U[100][2048][2048];
But the following dynamic allocation goes fine
double ***U = (double ***)malloc(100 * sizeof(double **));
for(i=0;i<100;i++)
{
U[i] = (double **)malloc(2048 * sizeof(double *));
for(j=0;j<2048;j++)
{
U[i][j] = (double *)malloc(2048*sizeof(double));
}
}
The ulimit is set to unlim
I was mistakenly copied an iso into my external hard drive!
# dd if=iso.iso of=/dev/sdb oflag=direct bs=1M
^C83+0 records in
82+0 records out
85983232 bytes (86 MB) copied, 2.34214 s, 36.7 MB/s
It's not finished though. Hurriedly pressed ctrl+c to stop it. I could still play videos in my external hard drive but I'm worried. Is it okay? Or not?
Email this page
