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What's the easiest way to wipe HDD label & Partition info off drive? - Printable Version

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What's the easiest way to wipe HDD label & Partition info off drive? - weblacky - 07-25-2021

Hi,
  I'm experimenting with Irix OS installs...blanking the doot drive (ID1) enough to call it "empty" to try another install is seemly difficult.   I was hoping I could use what I do under linux and just DD the first 10MB or so of the drive to wipe all partitions and volume info so I could just re-FX everything. I'm afraid if I just mkfs on the root parittion that I'll still have old volhdr sash files stuff and such.  I'd rather the installer see the drive as blank...just easier.

Suggestions on how to do this without removing the drives. Can I just boot sash from CD and somehow run DD against partition 10?

OR can I reference the entire disk some other way from PROM miniroot to "blank" the used drive without low-level formatting it (I don't want this after I've already done it once on a disk during drive check-up).

Thanks!

RE: What's the easiest way to wipe HDD label & Partition info off drive? - Raion - 07-25-2021

yeah, there's an option for this. When in a miniroot install:

admin

This brings up the admin menu, from here there's an option (forget the number) to format.

That does the trick Smile

RE: What's the easiest way to wipe HDD label & Partition info off drive? - weblacky - 07-25-2021

Isn't format = low-level format like FX?

RE: What's the easiest way to wipe HDD label & Partition info off drive? - robespierre - 07-25-2021

More likely that only fx knows how to send SCSI FORMAT UNIT commands. Programs need to be linked against the SCSI library to talk to devices at a low level.

There are ways to do what you want, but what is the deeper reason for wanting that? There isn't anything really version-specific about the volume header or sash. I think the kernel is ECOFF throughout the history of Irix, so as long as the proper sash for the hardware architecture is installed it should work okay.

Yes, you can run sash from a CDROM (or a TFTP network server). Yes, you can blank a disk without low-level formatting it, from fx (use /exe/seq wr-only, and take the defaults).

If you know that you are using a 6.5 fx, you can use /auto. Note that 5.3 fx was bugged and did a (low-level) FORMAT when auto was selected (I guess on SMD/ESDI disks it was actually required and so the old behavior made some sense in the 1980s).

RE: What's the easiest way to wipe HDD label & Partition info off drive? - Raion - 07-25-2021

(07-25-2021, 01:34 AM)weblacky Wrote:  Isn't format = low-level format like FX?

No. it's a mkfs on the disk, which destroys all data.

RE: What's the easiest way to wipe HDD label & Partition info off drive? - weblacky - 07-25-2021

(07-25-2021, 02:28 AM)robespierre Wrote:  More likely that only fx knows how to send SCSI FORMAT UNIT commands. Programs need to be linked against the SCSI library to talk to devices at a low level.

There are ways to do what you want, but what is the deeper reason for wanting that? There isn't anything really version-specific about the volume header or sash. I think the kernel is ECOFF throughout the history of Irix, so as long as the proper sash for the hardware architecture is installed it should work okay.

Yes, you can run sash from a CDROM (or a TFTP network server). Yes, you can blank a disk without low-level formatting it, from fx (use /exe/seq wr-only, and take the defaults).

If you know that you are using a 6.5 fx, you can use /auto. Note that 5.3 fx was bugged and did a (low-level) FORMAT when auto was selected (I guess on SMD/ESDI disks it was actually required and so the old behavior made some sense in the 1980s).

Yeah, I was using irix 5.3...so...yeah saw "format" a little too often and got stuck in low-level formats 3 times (auto being one of them)...good thing I'm dealing with small drives.  I used Auto in 6.5 and never remembered this happening...odd you mentioned that...but I fell for that too!

So yeah I do have a real "big boy" reason for wanting the the drive appear empty. I'm going from 5.3 and 6.5.x...so I don't want any "cruft" in the volume header sections.  I don't want old sashes, UNIX.IPXX, and the like.  YES they are different for each disk (overlay) so I don't want to "mix and match".  The OS already does all this for me (on a blank drive) when I do label/create/all and partition/rootdrive under FX...OS install does the rest. I do not want it to find previous files in partition 8 and such.  I don't care about empty partitions...but they aren't empty right now and if I do a label/create/all and partition with ROotdrive under the installer for 5.3...it doesn't erase ANYTHING...just surfaces the old XFS filesystem and I've done nothing to help my case.

It's EASIER for me to have a blank drive than hope it gets upgraded as I go up and down the Irix version tree.

So you're saying you think a surface scan is the fastest way to wipe the drive...are you sure you don't  now a way to run a small overwrite the drive's first portion of space to wipe formatting/partition info so it just "looks" blank?  If I had a Linux Boot disk...it's just DD the front of the drive and it would be seen as blank. That's really what I'd pref to do.

RE: What's the easiest way to wipe HDD label & Partition info off drive? - Raion - 07-25-2021

There's no way to do this unless you wanna say, keep a spare scsi2sd around for your system, and then boot from that, and dd over the volume header of the drive to corrupt the data on it.

RE: What's the easiest way to wipe HDD label & Partition info off drive? - flexion - 07-25-2021

this is what I do when I want to install over an existing installation, or when the installer complains about "unable to mount partition realroot.."

$ bootp():/6.5.30/Overlay/disc1/stand/fx.64

enter write mode by answering yes. select disk..
in the main menu enter:

[r] to enter repartition menu
[ro] to repartition rootdrive, confirm with [y]
[..] to return to the main menu
[d/fi] to enter debug menu and fillbuf

buf offset = (0) press enter
fill string = () type [a] and press enter
nbytes = (524288) type 0x10000 and press enter

[d/w] to enter debug menu and writebuf
buf offset = (0) press enter
nblocks=(xxx) type [128] and press enter

[l/sy] to enter label menu and sync

then exit, restart and install IRIX

RE: What's the easiest way to wipe HDD label & Partition info off drive? - blacksmith - 07-25-2021

(07-25-2021, 01:34 AM)weblacky Wrote:  Isn't format = low-level format like FX?
The best results I had using  a Windows XP computer.

RE: What's the easiest way to wipe HDD label & Partition info off drive? - weblacky - 07-26-2021

(07-25-2021, 05:37 AM)flexion Wrote:  this is what I do when I want to install over an existing installation, or when the installer complains about "unable to mount partition realroot.."

$ bootp():/6.5.30/Overlay/disc1/stand/fx.64

enter write mode by answering yes. select disk..
in the main menu enter:

[r] to enter repartition menu
[ro] to repartition rootdrive, confirm with [y]
[..] to return to the main menu
[d/fi] to enter debug menu and fillbuf

buf offset = (0) press enter
fill string = () type [a] and press enter
nbytes = (524288) type 0x10000 and press enter

[d/w] to enter debug menu and writebuf
buf offset = (0) press enter
nblocks=(xxx) type [128] and press enter

[l/sy] to enter label menu and sync

then exit, restart and install IRIX
NICE, you found a way to write over the front of the drive..exactly what I wanted to do!  I'll try this out, thanks!