[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
* Mr. Drill Press enter the chat * Mrs. Dectape laughs at your attempts :-) C :) g.
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
On Fri, Mar 24, 2023 at 12:17 PM geneb via cctalk wrote: > On Fri, 24 Mar 2023, Tom Gardner via cctalk wrote: > > > Well the data are still there and could be retrieved with a > sophisticated servo on data system and/or a probe head on the data surfaces. > > Simpler to hit the spindle motor top dead center with a very large > hammer ruining the bearings and crashing a few heads in the process. > > Even then the data are still there so nothing beats a multi-pass full > disk wipe > > > > * Mr. Drill Press enter the chat * > The data is still where the holes aren't though ;) Sellam
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
On 3/24/23 12:17, geneb via cctalk wrote: > On Fri, 24 Mar 2023, Tom Gardner via cctalk wrote: > >> Well the data are still there and could be retrieved with a >> sophisticated servo on data system and/or a probe head on the data >> surfaces. >> Simpler to hit the spindle motor top dead center with a very large >> hammer ruining the bearings and crashing a few heads in the process. >> Even then the data are still there so nothing beats a multi-pass full >> disk wipe Tossing one into a burning slash pile works well, also. Melts that Zamac, it does. Don't ask me how I know. --Chuck
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
On Fri, 24 Mar 2023, Tom Gardner via cctalk wrote: Well the data are still there and could be retrieved with a sophisticated servo on data system and/or a probe head on the data surfaces. Simpler to hit the spindle motor top dead center with a very large hammer ruining the bearings and crashing a few heads in the process. Even then the data are still there so nothing beats a multi-pass full disk wipe * Mr. Drill Press enter the chat * :) g. -- Proud owner of F-15C 80-0007 http://www.f15sim.com - The only one of its kind. http://www.diy-cockpits.org/coll - Go Collimated or Go Home. Some people collect things for a hobby. Geeks collect hobbies. ScarletDME - The red hot Data Management Environment A Multi-Value database for the masses, not the classes. http://scarlet.deltasoft.com - Get it _today_!
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
Well the data are still there and could be retrieved with a sophisticated servo on data system and/or a probe head on the data surfaces. Simpler to hit the spindle motor top dead center with a very large hammer ruining the bearings and crashing a few heads in the process. Even then the data are still there so nothing beats a multi-pass full disk wipe -Original Message- From: Chris Zach [mailto:c...@beaker.crystel.com] Sent: Thursday, March 23, 2023 9:53 AM To: cctalk@classiccmp.org Subject: [cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone? Speaking from experience with an old RD54, yep. Put a magnet on the outside case towards the bottom, spin the drive up and it's gone forever. On 3/23/2023 12:22 PM, Daniel Daigle via cctalk wrote: > Old MFM/RLL drives with stepper positioners generally have no servo. > The same can't be said of voice-coil positioned drives; they could use > any means, including hardware optical servos, etc. but often used a > surface and a head for that purpose... so yes, you can render one of > these drives useless with a magnet if yours has a servo surface. (This > is not the same as embedded servo, which places servo information > -with- the data on the same surfaces.)
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
Speaking from experience with an old RD54, yep. Put a magnet on the outside case towards the bottom, spin the drive up and it's gone forever. On 3/23/2023 12:22 PM, Daniel Daigle via cctalk wrote: Old MFM/RLL drives with stepper positioners generally have no servo. The same can't be said of voice-coil positioned drives; they could use any means, including hardware optical servos, etc. but often used a surface and a head for that purpose... so yes, you can render one of these drives useless with a magnet if yours has a servo surface. (This is not the same as embedded servo, which places servo information -with- the data on the same surfaces.)
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
Old MFM/RLL drives with stepper positioners generally have no servo. The same can't be said of voice-coil positioned drives; they could use any means, including hardware optical servos, etc. but often used a surface and a head for that purpose... so yes, you can render one of these drives useless with a magnet if yours has a servo surface. (This is not the same as embedded servo, which places servo information -with- the data on the same surfaces.)
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
On Sun, Feb 5, 2023 at 11:12 AM emanuel stiebler via cctalk wrote: > Keep "all" magnets away from disks :) The hubs of 3.5" floppy disks and of the disk packs used in RK05s, RL01s/02s, RK07s, etc are locked to the spindle by a ring magnet. -tony
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
On 2023-02-03 21:28, Chris Zach via cctalk wrote: Perm magnet. Those neodynium magnets are powerful, keep them away from disks. Keep "all" magnets away from disks :)
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
Perm magnet. Those neodynium magnets are powerful, keep them away from disks. C On 2/3/2023 9:26 PM, Tom Hunter via cctalk wrote: Chris, what kind of magnet did you use? If it was an electromagnet I could imagine that you caused physical damage by something heating up sufficiently. If it was a permanent magnet then it might indeed be servo data which has been erased. Either way I expect you need a very strong magnetic field to erase a hard drive from the outside. Tom On Sat, 4 Feb 2023, 12:40 am Chris Zach via cctalk, wrote: Question: I just used a strong magnet to wipe an old Maxtor MFM drive (magnet on outside of case). Now the drive will not even seek properly on start up, just endlessly moves the heads.. Is the drive now toast? Do MFM drives have embedded servo information on the platter formatted by the factory? CZ
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
On 2023-02-03 11:57, Chris Zach via cctalk wrote: This is a Maxtor 2190. The RD54 base disk. I've been having major problems trying to format them on my RQDX3, I'll post that adventure in a bit. In a nutshell the drives only partially format then error out. On Dave G's MFM emulator all the tracks appear to be there. OK, is it a MAXTOR 2190, or a RD54? If it is really an RD54, it has the weird DEC sectors with the bad block information. If it doesn't have the bad blocks information written in the "DEC way" it won't be recognized as a RD54
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
Chris, what kind of magnet did you use? If it was an electromagnet I could imagine that you caused physical damage by something heating up sufficiently. If it was a permanent magnet then it might indeed be servo data which has been erased. Either way I expect you need a very strong magnetic field to erase a hard drive from the outside. Tom On Sat, 4 Feb 2023, 12:40 am Chris Zach via cctalk, wrote: > Question: I just used a strong magnet to wipe an old Maxtor MFM drive > (magnet on outside of case). Now the drive will not even seek properly > on start up, just endlessly moves the heads.. > > Is the drive now toast? Do MFM drives have embedded servo information on > the platter formatted by the factory? > > CZ >
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
On Fri, Feb 3, 2023 at 5:21 PM Alexandre Souza wrote: > > I thoug the right one was st512...can you enlighten me on this subject Tony? I've never heard it called that. It's often called 'ST506' but that drive had a few differences from the later ones. it didn't support buffered seeks AFAIK. The ST412 did and was the most common of a family of 3 similar drives (ST406, ST412, ST419) so it tends to be used as the de-facto name of the interface. -tony
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
Or ST506 ? On Fri, Feb 3, 2023 at 5:21 PM Alexandre Souza via cctalk < cctalk@classiccmp.org> wrote: > I thoug the right one was st512...can you enlighten me on this subject > Tony? > > Enviado do meu Tele-Movel > > > > I assume by 'MFM' you mean a drive with an interface similar to the > ST412. > > -tony > > >
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
I thoug the right one was st512...can you enlighten me on this subject Tony? Enviado do meu Tele-Movel > I assume by 'MFM' you mean a drive with an interface similar to the ST412. > -tony >
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
On Fri, Feb 3, 2023 at 4:57 PM Chris Zach via cctalk wrote: > Yep, with 15 yeads it had a servo platter that is gone. Oh well, it's > securely erased :-) I'll toss the drive, keep the electronics interface > and keep it in mind for the future. If you have the tools, it's worth carefully dismantling the dead HDA taking photos as you go and keeping parts like the heads and flexiprint. Other bits like the positioner magnet and spinde motor mght be worth keeping too. Some months ago I was working on a Toshiba hard drive in a Stride 440 and I wish I'd had some idea of what was on the flexiprint between the logic board connector and the heads. Of course without a clean room I didn't dare open the HDA, but had a defective or dismantled one been available I'd have paid reasonable money for it. -tony
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
Embedded servo is rare (unheard-of) on ST412 interfaced drives simply because the manufacturer has no idea how it will be low-level formatted and thus where the sector headers will be. So no safe place for the servo bursts on the data surfaces *nod* That's what I would think: MFM should allow you physical access to the heads to write the format as you see fit. So head positioning should be mechanical, not servo based. But a dedicated servo surface is very common on larger such drives. That's why you often see an odd number of data heads. There is a head on each side of each disk, but one is used for the servo. This is a Maxtor 2190. The RD54 base disk. I've been having major problems trying to format them on my RQDX3, I'll post that adventure in a bit. In a nutshell the drives only partially format then error out. On Dave G's MFM emulator all the tracks appear to be there. Sounds like you've wiped that. No sensible way to recover I'm afraid Yep, with 15 yeads it had a servo platter that is gone. Oh well, it's securely erased :-) I'll toss the drive, keep the electronics interface and keep it in mind for the future. C
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
On Fri, Feb 3, 2023 at 4:40 PM Chris Zach via cctalk wrote: > > Question: I just used a strong magnet to wipe an old Maxtor MFM drive > (magnet on outside of case). Now the drive will not even seek properly > on start up, just endlessly moves the heads.. > > Is the drive now toast? Do MFM drives have embedded servo information on > the platter formatted by the factory? I assume by 'MFM' you mean a drive with an interface similar to the ST412. Embedded servo is rare (unheard-of) on ST412 interfaced drives simply because the manufacturer has no idea how it will be low-level formatted and thus where the sector headers will be. So no safe place for the servo bursts on the data surfaces But a dedicated servo surface is very common on larger such drives. That's why you often see an odd number of data heads. There is a head on each side of each disk, but one is used for the servo. Sounds like you've wiped that. No sensible way to recover I'm afraid -tony
[cctalk] Re: Nuking an MFM drive with a magnet, format/servo gone?
low level format On Fri, Feb 3, 2023 at 11:40 AM Chris Zach via cctalk wrote: > Question: I just used a strong magnet to wipe an old Maxtor MFM drive > (magnet on outside of case). Now the drive will not even seek properly > on start up, just endlessly moves the heads.. > > Is the drive now toast? Do MFM drives have embedded servo information on > the platter formatted by the factory? > > CZ >
