Poll: Floppy disk controller

[+OLD CS1]

If I remember correctly, all my C64 friends with their 1541 floppy drive were pretty envious of me and my TI floppy drive which, even at single density speed, was a lot faster.

 

OH, yeah. The 1541 communicates natively around 300 cps-ish because of a flaw dating back to the VIC-20's 6522 VIA (versatile interface adapter) chips. The VIC-20 and 1540 were supposed to use the bit-shift register in the 6522 to communicate but it turned out to have a major flaw. Instead, Commodore engineers had to do the bit-banging in the Kernal. The Commodore 64's 6526 CIA (complex interface adapter) was supposed to fix this, but (according to Bagnall) when the board designs were sent from West Chester to California for manufacturing, someone reviewing the drawings found a trace which he did not think should be there -- it turned out to be the trace which would have linked the 6526's bit-shift register to the serial bus. This was not corrected until the Commodore 128 and the 1571, which implemented the intended design and called it "burst mode."

 

EDIT: There is at least one hack which will connect the 6526 bit-shift register to the serial bus to activate burst-mode transfers, but it requires a Kernal modification to use natively which still does not work with the 1541. By the time you do all this, you could just install JiffyDOS which works perfectly well and is quite inexpensive.

 

Another EDIT: Incidentally, the Commodore 64 is actually SLOWER than the VIC-20 when communicating on the serial bus due to the enhanced features of the VIC-II video chip. The VIC-II and 6510 share memory, and when the VIC-II needs additional time on the buss it can stop the 6510, which causes slower communications. I believe this is also why we were told the 64 could never run a modem at 2400 bps.

[+OLD CS1]

I have a local fellow hobbyist who is selling a bunch of Commodore 64 and Apple items and some of those items are External Floppy Drives so I have access to them. Is it the same situation with an Apple IIe "DISK II" External Floppy Drive?

 

Yes. The Apple floppy drives are just mechanisms. The standard drives used by the TI (which are essentially PC drives) contain decoding circuitry on-board, which the Apple drives lack. Additionally, Apple also uses a form of GCR.

[+OLD CS1]

Is there a DSR EPROM which makes the BwG controller show dates in English?