Archive for 0xDEAD

Zfs versions feature madness

Posted in software with tags , , , on 2008.04.22 by ipv5

Feature creep? This is feature madness! This is SpartaZFS!
just go to http://opensolaris.org/os/community/zfs/version/1/ and increment the last number (or, read on, might as well write it down as I read) for all the goodies [thet keep gettin] added to zfs.

  1. This is the initial ZFS on-disk format as integrated on 10/31/05
  2. Support for “Ditto Blocks”, or replicated metadata. Metadata can be replicated up to 3 times for each block, independently on the underlying redundancy. (i.e.: if you have a raid1 on two disk, you get 6 copies of the blocks you deem important) So even if your user data get corrupted everything (fingers crossed) will still be discoverable and the pool will be useable.
  3. Hot spares, improved RAID-Z accounting (does not mention how it get improved however), and support for double-parity RAID-Z (aka raidz2, aka suspiciously-looks-alot-like-raid6).
  4. zpool history. A log of whatever happens to your pools
  5. gzip compression for zfs datasets. Your /usr/ports is now very happy (remember to mount /usr/ports/distfiles elsewhere however)
  6. ‘bootfs’ pool property. (yes, it does what it looks like it does)
  7. With the ZFS Intent Log (ZIL) an application (a database usually) does know that whatever it did just wrote to disk will stay written even if a power failure occurs. Instead of waiting a second or two for the zfs to do all its magik, there’s a transaction log in which fsync(fd)s are stored, so the database can churn away happily without having to wait. If power failure occurs between zfs disk commits, this log is read and committed to disk as well.
  8. Administrative tasks (such as creation/of descendent datasets) can be assigned to non-administrative users. While this is a bit scary, remember we can assign quotas to the parent dataset
  9. Dataset quotas and reservation can be configured not to include descendent datasets (such as snapshots/clones) in the space consumption cap. And there’s support for the sun cifs server as well
  10. You can specify a device in the zfs pool to act as cache. “These devices provide an additional layer of caching between main memory and disk. Using cache devices provides the greatest performance improvement for random read-workloads of mostly static content.” You know what a cache is, and there’s way too much math for me to go look at the detailed performance improvement.

interesting links:
nice recap of avaiable solaris filesystems

easy introduction to zfs, and way-too-much-math introduction to zfs2

zfs cheat sheet

introduction to ZIL and more in-depth stuff as well

List of zfs administrative tasks which can be delegated, along with a nice primer

configuring the cifs server to use zfs datasets, for workgroups and with active directory

edit: a very interesting blog about building an home fileserver using ZFS, and the ZFS Evil Tuning Guide.

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List of hard disk ata master passwords

Posted in hardware with tags , , , , , on 2008.04.14 by ipv5

Ferreted this out after some hours of web searching, guess I can spare you the same trouble

If you find this stuff useful, please do leave a comment, “hi, it worked” is enough.

(nb: see my previous post for unlocking instructions)

SEAGATE -> “Seagate” +25 spaces

MAXTOR
series N40P -> “Maxtor INIT SECURITY TEST STEP ” +1 or +2 spaces
series N40P -> “Maxtor INIT SECURITY TEST STEP F”
series 541DX -> “Maxtor” +24 spaces
series Athena (D541X model 2B) and diamondmax80 -> “Maxtor”

WESTERN DIGITAL -> “WDCWDCWDCWDCWDCWDCWDCWDCWDCWDCWD”

FUJITSU -> 32 spaces

SAMSUNG -> “ttttttttttttttttttttttttttttttttt” (32 times t)

IBM
series DTTA -> “CED79IJUFNATIT” +18 spaces
series DJNA -> “VON89IJUFSUNAJ” +18 spaces
series DPTA -> “VON89IJUFSUNAJ” +18 spaces
series DTLA -> “RAM00IJUFOTSELET” +16 spaces
series DADA-26480 (6,4gb) -> “BEF89IJUF__AIDACA” +15 spaces

HITACHI series DK23AA, DK23BA and DK23CA -> 32 spaces

TOSHIBA -> 32 spaces

For xbox hdds try “XBOXSCENE” or “TEAMASSEMBLY” too

Halt and Catch Fire

Posted in hardware with tags , , , , , , on 2008.04.10 by ipv5

Got a disk for cheap off ebay, since the user forgot the ata password. Turned out the disk was 0xDEAD anyway, but I’ve learned a bit more about the ata/pata commands.
If you got a locked disk and do not care much for the contents read on.

First thing first: you really do want to go pay HddGuru a visit, they host some really great tools like mhdd (which lets you send ata commands directly to the disk), a forum, and of course the ATA/ATAPI-8 revision 2b — AT Attachment — 8 ATA/ATAPI Command Set (January 10, 2006). A not-in-any-way-dull list of all the stuff you can send to your disk, including HCF but sadly lacking RAISE_FROM_THE_DEAD.

Ok, let’s grab/burn our Ultimate boot CD (mhdd is under the diagnostic tools btw) and fire it up.
Select your locked disk (1 usually) and let’s ask IDENTIFY to the bugger. Yes, that’s way too much info.

The first thing to look for is the 8th bit in the 128th word, 0 is security=high, 1 is security=maximum.

If it’s zero we’re in luck, and we can either unlock the disk with the regular password (assuming you know it, I did not) or with the master password (you can find some of them on the net, just google for your model number). (edit: I’ve collected the passwords I’ve found here)

Let’s type UNLOCK, and reply 1 when asked [that means we’re using the master’s password], and enter our password.
If we do not get an error [ERR turns red on the top of the screen] we’re good to go, if we do there’s 4 more tries with the password before we need to powercycle the disk.
If we get the password right a DISPWD (followed by 1 and the password again) will stop all this locking nonsense for good.

Oh, right, there’s maximum security too.
Well, that’s more satisfacting if slow as a glacier.
Just send an ERASE PREPARE followed by an ERASE UNIT and after an hour or so you can go and DISPWD it for good. Yes that will erase it completely, told you it was more satisfacting.

list of interesting stuff from identify:

  • bit 8 in word 128: security, 0=high 1=maximum
  • word 92: if it’s 0xFFFE the master password is unchanged (and you could get lucky and find it on the net)
  • words 89 and 90: how long will it take to ERASE the disk
  • word 88: which kind of dma the disk supports
  • byte 2 in word 53: wheter the fields in word 88 are valid or not (wtf?)

list of interesting links:

Happy disk hacking everyone

tags for the spiders: how-to howto unlock a password protected hard disk hdd