Search found 5 matches

by philpem
Sat Dec 31, 2011 9:01 pm
Forum: Support
Topic: Index position in 3.5" drives
Replies: 1
Views: 933

Re: Index position in 3.5" drives

Bit late but I think I might have something to add... What I would do in this situation (if replacing the drive wasn't an option -- 3.5in drives are basically two a penny these days) is use a known good drive to DC-erase an entire track, then on the second pass write a burst of data when the index s...
by philpem
Sat Dec 31, 2011 8:50 pm
Forum: Support
Topic: Seagate ST-225 hard drive
Replies: 4
Views: 1922

Re: Seagate ST-225 hard drive

Unfortunately the I/O ports used by the old controller cards for these drives happen to be the same I/O ports used by IDE controllers, so you'll have a very difficult time getting an IDE drive working in the same machine as an ST-506, unless you're lucky enough to find two boards that are very cust...
by philpem
Sun Jul 10, 2011 10:02 pm
Forum: Support
Topic: 2.88 Mb floppy support?
Replies: 9
Views: 3383

Re: 2.88 Mb floppy support?

I am pretty confident that 1.44 drives have a bandpass that will filter out the speedy reversals found on a 2.88MB disk... Some will. But the main filter is a high-pass: "pass anything of X frequency or faster". After some experiments writing white noise and various bit patterns, I figured that mos...
by philpem
Tue Feb 01, 2011 3:22 pm
Forum: Support
Topic: 3.5" and 3" disks on the same cable possible?
Replies: 8
Views: 2352

Re: 3.5" and 3" disks on the same cable possible?

The control protocol for the Amstrad EME-series drives is basically the same as standard 3.5in drives (with the exception of the READY output which most modern 3.5in drives don't provide). All you need to put a 3.5in and a 3in on one cable is a suitable adapter -- from 34pin PC to Amstrad 26pin. Two...
by philpem
Tue Feb 01, 2011 3:12 pm
Forum: Feature Requests
Topic: Bad sector repair
Replies: 7
Views: 2451

Re: Bad sector repair

You can -- in theory -- run the CRC backwards to find the erroneous bits. It's basically how the old MFM hard drives worked -- generate a 32-bit CRC for each sector, then verify it when reading (note that CRC32(concat(data, CRC32(data))) = 0). If the CRC check fails, then the result of crc32(concat(...