[9fans] Q: checking CD vs. iso image

[9fans] Q: checking CD vs. iso image

[pac7]

hi,
how do i check content of a CD versus an iso image from which it
was burnt (using md5sum and cmp, perhaps)?

thanks, cheers,
++pac


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Re: [9fans] Q: checking CD vs. iso image

[Russ Cox]

> how do i check content of a CD versus an iso image from which it
> was burnt (using md5sum and cmp, perhaps)?

md5sum original.iso
md5sum /dev/sdD0/data

you may have to eject the disk and put it back in to
make plan 9 realize the cd has changed underfoot.

russ

Re: [9fans] Q: checking CD vs. iso image

[Uriel]

Having a way to identify the build date of ISO images would be very
nice(like what VN does for Inferno images).

Also having the .iso images files accessible with date-based names would
make it easier to maintain mirrors and point people to known "good"
images if they have problems with the installation.

uriel

On Mon, Aug 22, 2005 at 02:08:29PM +0200, pac7@post.cz wrote:
> hi,
> how do i check content of a CD versus an iso image from which it
> was burnt (using md5sum and cmp, perhaps)?
> 
> thanks, cheers,
> ++pac
> 
> 
> -- 
> Ziskejte trvale pripojeni k internetu VOLNY ADSL za nizky mesicni
> pausalni poplatek 349,- Kc mesicne. Revoluce na internetu jiz
> zacala! Vice informaci ziskate na http://adsl.volny.cz/
> 

Re: [9fans] Q: checking CD vs. iso image

[Russ Cox]

> Having a way to identify the build date of ISO images would be very
> nice(like what VN does for Inferno images).
> 
> Also having the .iso images files accessible with date-based names would
> make it easier to maintain mirrors and point people to known "good"
> images if they have problems with the installation.

You only need a "good" list if "bad" is the norm.
If "bad" is the norm, let's address that instead.

I don't want to save every CD image (they change almost
nightly).  It's a waste of disk space (Venti doesn't help
because the images are compressed and thus share
no common blocks).  VN updates their CDs much less
frequently than we do, so it's not as big a deal for them.

If you're dying to identify an old image, use
http://plan9.bell-labs.com/plan9checksums.txt.

Russ

Re: [9fans] Q: checking CD vs. iso image

[Gorka guardiola]

On 8/22/05, Russ Cox <russcox@gmail.com> wrote:
> You only need a "good" list if "bad" is the norm.
> If "bad" is the norm, let's address that instead.
> 

Bad is as in badly compressed (that is easy to check for, you uncompress,
mount, diff the trees) or bad meaning a bug in a program inside the
CD?. Booting the
CD in a virtual environment may help on that, though it may be too
much of a hassle.
-- 
- curiosity sKilled the cat

[9fans] Q: checking CD vs. iso image

[alexandr babic]

hi.

and what about to compare one byte from cd with one byte from iso
by following short program, but i haven't plan9 here so you have 
to try by yourself :-)

alexandr.


check.c
------------------------------
#include <u.h>
#include <libc.h> 

void main()
{
int cdfd,isofd,i,r;
unsigned char C,I;

cdfd=open("/dev/sdD0/data",OREAD); 
isofd=open("obraz.iso",OREAD); 

i=0;

while(1)
{
 r=read(cdfd,(void*)&C,1);
 if(r==0) break;
 r=read(isofd,(void*)&I,1);
 if(r==0) break;
 i++;

 if(C==I) print("byte position=%d, bytes are same!\n",i);
 else print("byte position=%d, bytes differ! cd is %d, iso is %d
\n",i,C,I);
}

close(cdfd);
close(isofd);
exits(0);
}

Re: [9fans] Q: checking CD vs. iso image

[Anselm R. Garbe]

On 8/22/05, alexandr babic <alexandr@babi.cz> wrote:
> while(1)
> {
>  r=read(cdfd,(void*)&C,1);
>  if(r==0) break;
>  r=read(isofd,(void*)&I,1);
>  if(r==0) break;
>  i++;
> 
>  if(C==I) print("byte position=%d, bytes are same!\n",i);
>  else print("byte position=%d, bytes differ! cd is %d, iso is %d
> \n",i,C,I);
> }

That produces much output and the speed might be too fast to notice a diff ;)

while(1) {
....
    if(C != I)
        exits("cd and iso differ at least at byte position %d\n");
}

print("cd and iso are equal\n");

...

Regards,
-- 
  Anselm R. Garbe  ><><  www.ebrag.de  ><><  GPG key: 0D73F361

Re: [9fans] Q: checking CD vs. iso image

[Gorka guardiola]

Congratulations, you just reinvented cmp(1). You should now go for ps(1).

On 8/22/05, alexandr babic <alexandr@babi.cz> wrote:
> hi.
> 
> and what about to compare one byte from cd with one byte from iso
> by following short program, but i haven't plan9 here so you have
> to try by yourself :-)
> 
> alexandr.
> 
> 
> check.c
> ------------------------------
> #include <u.h>
> #include <libc.h>
> 
> void main()
> {
> int cdfd,isofd,i,r;
> unsigned char C,I;
> 
> cdfd=open("/dev/sdD0/data",OREAD);
> isofd=open("obraz.iso",OREAD);
> 
> i=0;
> 
> while(1)
> {
>  r=read(cdfd,(void*)&C,1);
>  if(r==0) break;
>  r=read(isofd,(void*)&I,1);
>  if(r==0) break;
>  i++;
> 
>  if(C==I) print("byte position=%d, bytes are same!\n",i);
>  else print("byte position=%d, bytes differ! cd is %d, iso is %d
> \n",i,C,I);
> }
> 
> close(cdfd);
> close(isofd);
> exits(0);
> }
> 
> 


-- 
- curiosity sKilled the cat