Subject: Re: [linux-audio-dev] hdr disk throughput
From: David Olofson (david_AT_gardena.net)
Date: Wed Mar 15 2000 - 22:34:36 EST
On Mon, 13 Mar 2000, Paul Barton-Davis wrote:
> i am a little worried.
>
> it seems to me that in order to offer "true professional level" HDR,
> one has to sustain twice the apparent rate of disk i/o.
Yes. All dedicated systems I know of have significantly more
performance headroom than that, as they also need to be able to
handle quite a great deal of fragmentation as well. (Hmm... They even
have these dreaded defrag tools you have to run every now and then.
What about adding some 15-25% extra disk space and a real,
non-fragmenting fs instead?)
[...]
> thus, in a record-all-tracks situation, to offer this feature, you
> have to be able to stream the given data rate both to *and* from the
> disk.
Well, I can't se any way around this. Even though you can use any
amount of buffering you need to reduce the seek stress from
recording, the data still has to be written to disk, eventually.
Of course, you could use that "Pre-Arm" thing some systems use, but
I'd prefer not see that ever again, if it can be avoided... *Stop*
playback to select what tracks will record when you press REC during
playback!? Naah... Cludge. Also, it doesn't protect from overloading
the disk any better than checking the load before engaging each during
playback track would do. You still can't get more tracks than you
machine can cope with - you'll only have a slightly earlier warning.
Make sure to get a fast enough disk if you never want any "surprizes"
when fiddling with record switches during playback.
//David
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