Kitz Forum
Computer Software => Linux => Topic started by: tickmike on March 28, 2008, 12:43:29 AM
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Under Linux I have done a md5sum on a pclinux minime download.iso , And it was the same as the one on the web site. ;).
So if I now burn a disk from that .iso , would you have to run a check on it, If so how ?.
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>> would you have to run a check on it, If so how ?.
If you have already run a "Checksum" verifier on the material you have downloaded then you have confirmed that it is the genuine article and and not a fake masquerading as the item you wanted, so there would be no need to run it again.
On the off-chance I am not reading your post quite right and you do not have a Checksum program:
The program I used to use is called "MD5-Filealyz" it's approximately 1.8MB and also a free DL but from where I can't remember.
If you don't have any success with a search on the web, just let me know and I will email it to you.
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Or, you can get a similar one from here.
http://www.softpedia.com/get/Security/Security-Related/Md5Checker-Publisher-Md5Checker.shtml
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In principle you should check the md5sum of the burned CD, because the burning process can introduce errors. The easy way (but not always correct) is to type:
md5sum /dev/cdrom
The problem with this is that sometimes extra padding bytes are added by the burner, so the CD will have a different MD5Sum even though it's been burned correctly. There's a full discussion of the issue here. (http://twiki.org/cgi-bin/view/Wikilearn/CdromMd5sumsAfterBurning)
To be honest, most people would say that it's more trouble than it's worth (and I've never bothered). If you have any doubts about the quality of your CD/DVD writer, then do the burn at a low speed and always use good quality branded CDs.
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Just out of curiosity, I just ran this check on a CD I recently burned with k3b, and the md5sums did match, so it looks as though k3b doesn't add padding bytes when burning.
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... or the ISO was correctly padded anyway?
(just to play devil's advocate! >:D )
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Thank you Chris :P
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Thanks.
I do had a xp md5sum (thanks oldfogy :) ) but I'm trying not to use xp ;).
I was having a padded paddy last night trying to check this cd.
I was using md5sum /dev/cdrom but getting this .
Password:
[root@kitchen ~]# md5sum /dev/cdrom
md5sum: /dev/cdrom: Input/output error
[root@kitchen ~]#
If I remember correctly I burnt this disk with K3b and it gave the sum at the end of the burn and it was correct, so it should be ok .
But why am I getting this 'Input/output error' is it due to this 'padding' ?.
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It may just be that on your system the device reference is something other than /dev/cdrom. Most Linux systems have /dev/cdrom as a symlink pointing at the first CD/DVD device, but yours may not. Depending on which IDE interface it's on, and whether its master or slave, it might be /dev/hdb, /dev/hdc or /dev/hdd. Of course there has to be a CD in the drive at the time.
By the way, you don't need to be root to run the command; you should be able to run it as a user.
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It may just be that on your system the device reference is something other than /dev/cdrom. Most Linux systems have /dev/cdrom as a symlink pointing at the first CD/DVD device, but yours may not. Depending on which IDE interface it's on, and whether its master or slave, it might be /dev/hdb, /dev/hdc or /dev/hdd. Of course there has to be a CD in the drive at the time.
By the way, you don't need to be root to run the command; you should be able to run it as a user.
I'm now thinking there is something wrong with this disk, Below is the disk (first line), Then I tried another Linux disk for something else.
[root@kitchen ~]# md5sum /dev/cdrom
md5sum: /dev/cdrom: Input/output error
[root@kitchen ~]# !!
md5sum /dev/cdrom
5f8e52583781bd74081dd90c970c6ea5 /dev/cdrom
[root@kitchen ~]#
I have use this first disk to do an install on two different computers and they have both got problems opening the same programs,
so that's what made me look at there checksums (even though K3b burner gave the correct sums :'( ).
I think I will burn it again. ( I use x4 speed ).
Thanks ref Terminal 'user' .
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To be honest, most people would say that it's more trouble than it's worth (and I've never bothered).
The program I used to use is called ......
As Roseway pointed out, yes sometimes it's more trouble than it's worth, hence the reason I no longer bother to do the check.
"If it works, it works"
If not, try again, sorry if that motto may not be to everyone's liking.
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To be honest, most people would say that it's more trouble than it's worth (and I've never bothered).
The program I used to use is called ......
As Roseway pointed out, yes sometimes it's more trouble than it's worth, hence the reason I no longer bother to do the check.
"If it works, it works"
If not, try again, sorry if that motto may not be to everyone's liking.
Well i'm a bit like that, But I have spent two weeks trying to solve why one of my programs will not work on two computers, common link the cd disk !.
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I appreciate we are talking Linux,
But I had/have a similar problem with XP and a music program, MusicMatch JukeBox.
It works in XP (no bother)
But it wont work if I install IE7
It even works in Vista
(although Vista says it can't work because it's not compatible "but it does when I click "Run Anyway") and thats with IE7.
So where do we go from here.
My point being, is it the OS or a conflict with another program?
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I was just about to re-burnt that cd, in the machine I burnt on in the first place.
Now how do you explane this.
I did a checksum.
[tickmike@office ~]$ md5sum /dev/cdrom
a2dbaa9167afb8a47efc936dc90132df /dev/cdrom
[tickmike@office ~]$
md5sum : a2dbaa9167afb8a47efc936dc90132df This is from the download site. and it looks like they match.
On three other machines I got this error. md5sum: /dev/cdrom: Input/output error :o Two had the same make and type of burner.
So what's that about ?. :'(
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Sorry it's beyond my knowledge.
(Probably why I don't bother with it)
But I do appreciate you are having problems and that may/is one way of trying to find the problem.
Hope you can get it resolved.
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edit.
Hope this is not too dumb a question, but is the program installing?
or are you just trying to figure-out the checksum problem?
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On three other machines I got this error. md5sum: /dev/cdrom: Input/output error Shocked Two had the same make and type of burner.
So what's that about ?.
Have you checked if /dev/cdrom actually exists on the other machines?
Of course, as OK infers, the important thing is that you've got an md5sum from the CD, and it does match the value from the download site, so the CD is OK.
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Have you checked if /dev/cdrom actually exists on the other machines?
Yes I have used them many times.