| Catweasel 1 |
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The original Catweasel card was one of the first to use an FPGA based sampler to read
data from a disk. A clock measures the time between flux transitions. The values are read
by a program and analysed. The clock can be 7.083MHz, 14.166MHz, 28.322MHz. This is enough
for most non High-Density floppies.
Nowadays ISA slot based machines are getting rare. BTW, there is a Catweasel MK2, but it has
a Zorro connector, only found in some Amiga computers. |
| Catweasel MK4 (+) |
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The Catweasel MK3 and MK4 were developed to allow hardware assisted emulation of the
Commodore 64 and similar machines on a modern PC. You can connect original C64 joysticks and
there are sockets for real C64 SID-chips. The clock can be 14.166MHz, 28.322MHz, 56,644MHz.
The picture shows a Catweasel MK4+.
There are several packages interfacing with the PC based Catweasel cards:
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| DiscFerret |
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The DiscFerret uses the same concept of the Catweasels but uses USB as interface to a
host computer. The encoding of timing data for the flux transitions is even identical. The
clock rates are different; 25 MHz, 50 MHz and 100 MHz. This makes it possible to read MFM
and RRL encoded harddisks with a ST-412 or ST-506 interface.
Software for the DiscFerret is limited to a raw data dumper (Magpie) and an analysis program
(Merlin) for this data. There are several initiatives for supporting other formats, one
being my conversion for FM/MFM encoded disks.
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