ahhills@watmath.waterloo.edu (Arthur Hills) (08/02/90)
There has been discussions on the net about the hardware problems with the 1.44 Meg floppy disk drives. I am the hardware supervisor of one lab which contains 50 SE'30 all with this drive. We have been noticing the same problems as every one else on the net. Frequently the floppies that are in these drives would no longer boot the systems. They could not be formatted on a apple system. However they could be formatted on an 386 clone system.Usually between 1 and 8 different bad blocks would be found. At the start of term in January I decided to start with fresh disks in all of the machines. I took the floppies and started to look at them without reformatting them. After checking for bad blocks with the "SUM Tuneup" software, I found that there was a very interesting problem. The same blocks were showing up as bad on a number of different disks and quite often if more than one block was found to be bad the separation of the bad blocks was a multiple of 36. This was very unique. I contacted the Apple Technical Response Group in Toronto Canada as well as the floppy disk manufacture. After much discussion and sending disks to both of these facilities I finally received a verbal response from Apple and a written response from Kao Didak the manufacturer of the floppies. Apple informed me that there 2 different types of floppy drives were shipped in their products. An early version from Sony with a GREEN board as the controller and a later version with a BLUE board also from Sony. The early version did not have a phase-lock-loop circuit to regulate the speed of the floppy drive. The BLUE board unit has this circuit. Quoting a letter from Kao Didak " A Phase Lock Loop is an electronic control system which is used to maintain a specific drive speed. The system automatically compensates for load variations thereby guaranteeing a specific rotational speed within (1%). A drive with no such circuitry could have a rotational speed which varied considerably. Will drive speed affect writing/reading? Yes if this drive speed was varying more that 1% when writing, we would experience problems with bit placement. Later when we go back to read the same portion of the disk track, the bit would appear to have shifted. This in turn could cause CRC (Cyclic Redundancy Check) errors." The solution has been to replace all the floppy drives in my machines with the BLUE board controller.
lius@utopia.rutgers.edu (Steve Liu) (08/03/90)
In article <1990Aug1.190114.600@watmath.waterloo.edu>, ahhills@watmath.waterloo.edu (Arthur Hills) writes: > > > There has been discussions on the net about the hardware problems with the > 1.44 Meg floppy disk drives. I am the hardware supervisor of one lab which > contains 50 SE'30 all with this drive. > I must have missed the previous discussion, but it's a topic I'm quite interested in, having attempted to format 100 disks, 40 of which formatted correctly, and 2 of which lasted more than one month without giving me a media error somewhere along the line (usually due to trying to re-format). > The solution has been to replace all the floppy drives in my > machines with the BLUE board controller. > Has this problem/solution been confirmed "officially"? If so, is there an upgrade policy, vis a vis the defective HD40? I told my dealer about the problem when I bought my machine two years ago; he told me there was no problem with the drive. I would like to start using the FDHD's capabilities, but have been afraid to trust it with important data as of late.
maarten@fwi.uva.nl (Maarten Carels) (08/20/90)
ahhills@watmath.waterloo.edu (Arthur Hills) writes: > There has been discussions on the net about the hardware problems with the > 1.44 Meg floppy disk drives. I am the hardware supervisor of one lab which > contains 50 SE'30 all with this drive. > The solution has been to replace all the floppy drives in my > machines with the BLUE board controller. > I looked into the drive inside my cx. I would call the colour of the board of the floppy blueish green (or greenish blue)... Is there any other way to recognize the drives (such as partnumbers, serial numbers being greater than some value, ...)? Is there any clue of the date Apple started using the newer (BLUE) devices. Is there a replacement program? Could someone from Apple shine a light on this ? --maarten -- In real life: Maarten Carels Computer Science Department University of Amsterdam email: maarten@fwi.uva.nl