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Old 03 June 2019, 09:33   #1
drHirudo
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Compression cards for Amiga?

While browsing through some old classic Macintosh software, I tested the Disk Doubler utility, which acts similar to PowerPacker and compresses files on the fly, thus effectively "doubling" the disk space. When running it I saw it searched for Double Up card and more search revealed this:
https://archive.org/stream/TNM_DiskD..._0204_djvu.txt

Quote:
DoubleUp is the first real-time lossless data compresĀ¬
sion card for the Macintosh NuBus family of personal
computers. It enables users to double the effective
storage capacity of their hard disks. Real-time means
that data, images, and applications can be compressed
and decompressed at speeds that are virtually unnotice-
able to the user. The lossless compression method
ensures that data is never lost or altered.
So my question is - did similar card exist for Amiga for on the fly compression/decomression?

I know the Delfina has DSP and there is the MAS player, which makes it effectively possible to replay MP3 files on 680x0 Amigas, but these are for decompression and for lossy (not lossless) formats.
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Old 03 June 2019, 13:54   #2
AmigaHope
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Nope, nothing like this was ever released to the best of my knowledge, unless you count some SCSI tape drives that have (transparent) hardware compression built in, or modems that did transparent compression on the data stream, but in both those cases the computer would never actually see the data in compressed form.

I suppose you could count WarpOS/PowerUp compression libraries that used the PPC as a coprocessor for 68k software.

As far as lossy compression goes there were a fair number of video compression cards like the DPS PAR, VLab Motion, and Newtek Flyer. Most of these cards had their own drive controllers on them to avoid using the Zorro bus, but you could still transfer around the compressed video files usually. These generally did realtime MJPEG encoding/decoding, but the Flyer used its own proprietary wavelet-based codec called VTASC. These cards were all built around the uncompressed data being decoded/encoded to/from their own video framebuffers, as the Z2 Bus was way too slow for uncompressed video, but you could probably use the VLab Motion as a generic JPEG coprocessor with some creative coding (though it was never used that way to my knowledge).

The Rembrandt video card supported hardware JPEG encoding, apparently.

EDIT: Also the KCS Dual HD floppy drive had a microcontroller in it that apparently included some sort of hardware compression (and a built-in low-level diskcopy routine!), but this still mostly falls under the transparent compression realm like with tape drives, etc -- but I guess you could write out a compressed floppy and then flip it to dumb-drive mode and read back the compressed image for storage elsewhere, but the format was undocumented so it wouldn't really serve any general-use purpose.

Last edited by AmigaHope; 03 June 2019 at 14:24.
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Old 05 June 2019, 15:37   #3
Hewitson
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I wasn't aware that any hard drive compression systems used cards. The PC ones I used all those years ago never required any additional hardware (Stacker, Microsoft Double/DriveSpace, etc).
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Old 05 June 2019, 22:30   #4
Frog
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hi,
it exists some transparent packed/unpacked system on amiga but as it doesn't use a specific hardware for this, it's not "virtually unnoticable to the user"


http://aminet.net/package/util/pack/PDPro1_0b
http://aminet.net/package/util/pack/XFH
http://aminet.net/package/util/pack/xfh-handler_os4
i know there's a solution to unpack/pack Powerpacker file transparently but i couldn't remember his name
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