Subject: Re: Disk ][ cards
From: Jeff.Brielmaier@juge.com (Jeff Brielmaier)
Date: Sat, Dec 19, 1998 11Ç58 
Message-id: <af8_9812200035@juge.com>

s >>I have some Disk ][ interface cards. They have 2 different part
s >>numbers. One is 600-0037 . Am I correct in assuming this is
s >>the first Disk ][ interface card? The other is 650-X104.
s >>Did Apple use any other numbers on their Disk ][ interface
s >>cards? I'm not counting theI/O controller of course*

s >One important difference has do with the PROMs on early
s >Disk II controller cards, which only supports 13 sector disks
s >(DOS 3.3 and ProDOS-8 require the 16 sectors PROMs). In all
s >my years an Apple II user, I've never seen a controller with
s >the original PROMs. They're quite rare as far as I know.

The reason why an original (13-sector) controller card is so rare, is 
that it could be converted to a 16-sector controller by simply 
replacing the P5 and P6 chips.  And I'd assume that most people had 
their Apple Dealer perform the update so that they could use the newer
software/operating systems.

Historical note: Apple's USCD P-System (Pascal) introduced both the 
16-sector disk format and the 16k memory card tothe Apple ][ world. 

 * KingQWK 1.05 # [PK] * To boldly go where no sane man has any business...