Ralph.Hyre@IUS2.CS.CMU.EDU (10/20/87)
What are the options in connecting disks to controllers to Apple // or Macintosh systems? I know of 4 controller systems I'd appreciate it if someone could fill in the gaps: Is this all thoroughly documented somewhere? I'd be happy to buy a book. 1) 'The Original' state machine thingie that Woz designed. 2) IWM - used in the Mac, //c and //GS. A modern version of 'the original' which can talk the 3.5 inch as well as 5.25 drives, even in 'IBM' (NEC 765 disk controller) format. 3) Protocol Converter (//c and //GS?) not really a controller, but a communications bus similar in principle to SCSI designed to talk to the integral controller in the UniDisk 3.5. A crippled version of this (no daisy-chaning of 5.25 drives) is what you get with the //e. Sigh. I'd like to know whether or not the Apple //e crippling was done in hardware or software. 4) SmartPort (//GS or on disk side of Protocol converter?) [Is this another name for the Protocol Converter?] It is claimed that if you have a 'smartport' drive (like the UniDisk 3.5) you can daisy chain large numbers (7 or 128) of ANY Apple drive including Mac external drives and old Apple 5.25 drivers to the back of it. - Ralph
fiddler%concertina@Sun.COM (Steve Hix) (10/23/87)
In article <561745777.ralphw@IUS2.CS.CMU.EDU>, Ralph.Hyre@IUS2.CS.CMU.EDU writes: > > 4) SmartPort (//GS or on disk side of Protocol converter?) > [Is this another name for the Protocol Converter?] > It is claimed that if you have a 'smartport' drive (like the UniDisk > 3.5) you can daisy chain large numbers (7 or 128) of ANY Apple drive > including Mac external drives and old Apple 5.25 drivers to the back > of it. This arrangement was first implemented on the //c when Apple did an upgrade on its ROM. (They had to fix some problems related to using 1200-baud modems anyway...) I got to write the description of the feature when I updated the //c Technical Reference Manual around the middle of 1985. You could daisy-chain <n> UniDisk 3.5s to the //c and access them with ProDos. While the software would permit up to 128 devices to be included in the daisy-chain, power supply restrictions limit the chain to seven devices. The last device in the chain could be a 5.25" UniDisk (A 400K Mac external drive would probably also fit, but I'd guess that you would need to much about with your own driver routines if you want to read Mac disks). Since a 5.25" UniDisk has no connector for another device to be connected, that pretty much follows.) By the way, the port is not limited to connecting disk drives. (The logical extension of that statement is an exercise left up to the reader.) seh