Has anyone put a proper shift register in a Commodore computer and floppy drive?

[bluejay]

I was enlightened of the reason why Commodore drives are so slow; buggy shift registers in the 6522s. Granted, I don't have an incredibly precise understanding on how the kernal handles the disk drive and vice versa, but wouldn't it be possible to hook up an 8 bit shift register to the data bus on both the computer and drive to make things a whole lot faster? If it is indeed possible, would it be incompatible with existing formats and media?

[bluejay]

To clarify, from what I understand Commodore decided the shift registers in the 6522s didn’t work so they decided to control everything in software which made things extremely slow. So, perhaps a cartridge that contains a shift register and the serial port, and an internal modification to the floppy drive that contains another shift register along with perhaps some RAM plus a bunch of programming would result in a fast floppy interface for Commodore computers. 

[brain]

A real shift register is in the 1571/1581 drives.  The C128 and those drives call its use "burst mode".  FOr the 64, you can use the existing shift register in the 64 to enable the same thing:

 

https://a1bert.kapsi.fi/Dev/burst/

 

[bluejay]

I was thinking of something in the form of a cartridge that would have a shift register that would plug into a modified 1541 to provide that burst mode speed on a C64. If that hardware was made to be compatible with the existing Commodore disk format then I assume it would be a nice little gadget.

[Tuxon86]

7 hours ago, bluejay said:

I was thinking of something in the form of a cartridge that would have a shift register that would plug into a modified 1541 to provide that burst mode speed on a C64. If that hardware was made to be compatible with the existing Commodore disk format then I assume it would be a nice little gadget.

Like a fast load cart?

[bluejay]

2 hours ago, Tuxon86 said:

Like a fast load cart?

A fast load cart is simply a bit of code that replaces the standard c64 floppy drive controlling routines. It is handy but it has its limitations... a really fast hardware shift register would make things a whole lot faster.