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| Title: | AMIGA NOTES |
| Notice: | Join us in the *NEW* conference - HYDRA::AMIGA_V2 |
| Moderator: | HYDRA::MOORE |
|
| Created: | Sat Apr 26 1986 |
| Last Modified: | Wed Feb 05 1992 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 5378 |
| Total number of notes: | 38326 |
3170.0. "Backup on video-tape" by FRSOLD::ZIMMERMANN (Ralf, DTN *861-3236, @FRS) Thu Nov 30 1989 11:42
A small German company (Superformance Hard & Soft) announced a backup-
system (Hardware/Software) which works with most Amigas and every
standart VHS/Video2000/Beta - VCR which has a camera-input.
It costs 148,- DM = US$ 65-70.
It works in the following way: The Program (Soft-part) connencts itself
to the driver of the device which you want to backup, reads the data
and redirects this data after some checkings over the serial port the
Box (Hard-part) which is there connected, and the VCR records the data
like a normal video-picture.
The netto-data-rate is 550 kBit/sec. That means a 20MB-disk-backup in
about 10-12 minutes. A 180-minutes VHS-cassette has a capacity of 400
MB.
They use different CRC-routines to avoid a data-loss during a drop-out
of the tape (the overall data-rate is 880 kBit/sec) and after the back-
up is a verify-option available. (like $ backup/verify ? maybe this
means another 10-20 minutes time to run ;-) ;-)
Every Amiga-device can be backuped/restored (DHn:, DFn:, RAD:)
Hardware recommendations: 1 MB-Amiga, VCR with a FBAS/BAS/Composite
or camera-input. The combination NTSC-Amiga/PAL-VCR is not supported.
(What about the combination NTSC-Amiga/NTSC-VCR ?)
Has anybody experiences with such a backup-solution? Years ago i saw ads
for the PC-world with a modified VHS-VCR (which accepts commands from
the PC, like BOT, EOT, REV, FF and so on; God, i loved the Tops-20-
Dumper)
I think if this beast works and there is a safe restore from a 1 year
old tape posssible, this would be a cheap way for a weekly full-backup
Ralf
====
| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 3170.1 | Failed bigtime in the IBM world | TLE::RMEYERS | Randy Meyers | Thu Nov 30 1989 18:26 | 10 |
| Re: .0
From what I heard, the VCR backup systems in the IBM clone world
turned out to be very, very unreliable, even with fault-tolerant
software. VCRs and VCR tapes just have too great of an error
rate to pull this off.
The last person to tell me about this pointed out that there was
only one company left that manufactures this sort of stuff in the
clone world. "A sure sign of a failed technology...," he stated.
|
| 3170.2 | | LEDS::ACCIARDI | | Thu Nov 30 1989 21:53 | 25 |
|
In another life we examined industrial strength VCRs for use as a mass
storage backup medium.
The problem with using a VCR is not the quality of the tape, as most
people think. The tape actually has fewer dropouts per square inch
than 1/2" computer tape.
The real problem is the mechanics of the VCR. Conventional streamer
and start/stop type tape mechanisms can very accurately and quickly
reposition the tape if an error is detected that can't be fixed on the
fly by an ECC (error correcting code). A VCR can take as long as
10 seconds to stop, back up and retry. Given that there will be
millions of errors per reel, it would take approximately forever to
ensure a backup with computer-company grade reliability.
Like 200 MPG carburators, I keep seeing this invention pop up from time
to time. I'd love to see someone get it working, but the best minds at
my old company threw in the towel.
Ed.
|
| 3170.3 | Agree with last reply | CSC32::K_APPLEMAN | | Fri Dec 01 1989 11:29 | 15 |
| I have seen vhs tape backup systems used on VAX's on a couple of my
old customers sites and they seem to work fine for them. Of course,
the tape drive mechanism is not a VCR. So just as the last reply
states, it isn't the quality of the tape, but the mechanism that
counts. I agree that a home vcr would never work properly with any
technology out there now. Maybe if someone came up with a cheap large
error correction code chip (reed-soloman) like in the ra series disk
drives. Something on the order of 100+ ecc bits might allow a lot of
data correction on the fly. Built in large scale buffering would also
be necessary to prevent having to backup the tape while error
correction
was going on. Doubt if we will ever see anything like this that is
cost effective.
ken
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