From: "Chuck B"
> jpbeale wrote:
>
>
>>> Not entirely. The battery died in one of my MD recorders after about 2
>>> hours of recording, so the TOC wasn't updated or finalized. But I was
>>> saved! There is a procedure online (I think someone on this list told
>>> me about it) to trick the Portadisc into loading the TOC from a
>>> fully-recorded disc, yanking the power, swapping MDs with the power
>>> off (some disassembly required), turning it on again whereupon a valid
>>> TOC is written to the damaged disc, which can then be played as usual
>>> (the chapters won't be there, but that hardly matters). I performed
>>> this procedure and it worked perfectly to recover my entire recording.
The procedure for this was given by HHb on the list, quite a while back
now. So a search of messages should produce the post.
Note with the portadisc, and some other recorders all you needed to do
when the battery died was put in fresh batteries and power up, the TOC
would have been written then. It's got it stored in nonvolatile memory.
> Very interesting, but ... Unless one sneaked by while I wasn't
> looking, all disk recording formats use the available space on the disk
> no matter where it is and except for a brand new or newly formatted
> disk, the files are not always contiguous. So, tricking a disk without a=
> TOC to play using an unrelated TOC you'd think the playback would jump
> in and out of the files instead of playing each file from start to
> finish. Did this happen to you?
This is the reason why one should always do important field recordings
either with a new disk or with a disk that's been fully erased of old
material. And don't edit the disk. Then each track will be in order,
otherwise you could be right. You'll have all the recording, but have a
editing job putting it back together if you don't follow this advice.
The arrangement of data on a minidisc was copied from that of audio CDs.
I always use new disks for my recordings and don't edit except to erase
a track I just started that went wrong occasionally. That track should
be at the end of what's recorded. And then the disk becomes the first
leg of my backup archive.
> Thought #2 - if it's this easy to recover a TOC, why can't Sony do it=
?
I asked HHb about this, and got something back that it was not in Sony's
description of approved functions for the pro Sony mechanism they used.
> Thought #3 - when the power went off on your MD, some kind of
> proto-TOC had been written and all it needed was a generic procedure to
> make it valid, which you did with your workaround. That leaves us with
> the same question about Sony - if you could do it, why couldn't they?
Actually, no TOC had been written. But in the case of the portadisc,
there is a TOC in memory and that's kept if the battery goes down. Next
time you power up that's written to disk. That's how the repair works.
This same trick works with other MD recorders, though some will preserve
enough power to write the TOC when the battery dies. I do not know what
the case is with HiMD.
Note the Portadisc only writes the TOC normally when you power down or
the disc is ejected. That's fairly common for minidisc recorders. So
running for long periods making lots of recordings without powering down
carries a certain risk.
Walt
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