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NuBus card to speed up decompression on IIfx?

Posted by: LaPorta on 2022-07-31 10:35:30

Hi everyone,

Are there any NuBus cards that will specifically speed up things like decompression on a IIfx? I am very happy with the base 030 speed for most things, but unstuffing things takes an absolute eternity. I wanted to know if there were cards made specifically for this.

Posted by: rieSha. on 2022-07-31 13:54:35

Not to my knowledge, at least not directly. Of course a Radius Rocket can do things faster, but it’s not really a card for decompression.

The problem really is StuffIt, mainly. Other decompressors are faster, but not as widespread.

Posted by: joshc on 2022-07-31 18:53:06

I find Stuffit decompression slow on most old machines, even 040s and various PPCs. The trick is to do the decompression on a faster machine and network transfer the decompressed stuff to your IIfx.

Posted by: LaPorta on 2022-07-31 18:56:32

Indeed, as I have been. I just was curious if anyone had come up with something like that, as there seems to be a card for everything in existance to some degree.

Posted by: Byrd on 2022-07-31 22:22:11

I recall in the x86 world there was an ISA based controller that accelerated DoubleSpace (MS DOS 6 compression utility), but nothing on Mac. Your best option LaPorta would be a RaSCSI device which you can extract files and copy over via network or SCSI, as an idea. I'm dabbling with one now, it's certainly a hobby-style solution not turnkey but is working quite well for download and mass copying of files.

Posted by: lobust on 2022-08-01 00:11:21

To answer the question directly (but not usefully), this is the kind of thing those RISC processor cards (I forget who made them or what silicon was onboard) would have been used for. Proprietary custom software of course, probably developed in-house by whoever had the need…

I use my vintage macs connected by Ethernet to a cheap Wi-Fi bridge/endpoint and have an ftp server running on a modern machine where I can decompress larger files prior to “downloading” on the old Mac.

Edit: like this one

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Posted by: Melkhior on 2022-08-01 01:12:32

The primary issue is (as always) software. For such a card to be useful, you'd need to be able to patch/write the software decompressor to make use of the hardware. Unfortunately, not much source code from that era survived (open-source was still only a limited thing on Unix and related systems), and in many cases even the algorithm/file format is not documented - for instance as far as I know, the StuffIt algorithm/file format is still 'proprietary'...
Then you need a piece of hardware which can do thing faster than the CPU; however, as for all such I/O-attached accelerator, you also have the overhead of sending the compressed data to the board and then sending back the decompressed data to the main memory. So your piece of hardware needs to be fast enough to still be faster when taking the overhead into account. Of course is the bus is slow relative to the CPU, the back-and-forth might already take more time than the CPU decompression, in which case no I/O-attached accelerator will help. The IIfx doesn't support NuBus block transfers (only Quadra and newer do), so the bandwidth you'd get from a NuBus device would be quite limited. A PDS device would be less restricted though, as it runs directly on the memory bus.