[net.micro.att] help with 6300 memory expansion, 6300+ drives, & interleave

jeffm@mmintl.UUCP (Jeffrey Miller) (02/17/86)

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On the subject of adding memory to the 6300:
	If 2 rows of memory (bank 0) are soldered and 2 are socketed, adding
256k chips in the 2 socketed rows (bank 1) to the 2 rows of soldered 64k
chips will give you 640k on the motherboard.  This is the optimum config.
DIP switch 0 (farthest from the edge of the board controls system memory.
 1 = on
 0 = off
 x = don't care
system memory	sw1 sw2 sw3 sw4 sw5 sw6 sw7 sw8
-------------	-------------------------------
 128kb		 0   1   1   1   x   x   x   x   128kb-motherboard
 256kb		 1   0   1   1   x   x   x   x   256kb-motherboard
 384kb		 0   0   1   1   x   x   x   x   256kb-motherboard &
						 128kb-expansion board
 512kb		 1   1   0   1   x   x   x   x   256kb-motherboard &
						 256kb-expansion board
 640kb		 0   1   0   1   x   x   x   x   256kb-motherboard &
						 384kb-expansion board
 512kb		 1   1   1   0   x   x   x   x   512kb-motherboard (bank 0)
 640kb		 0   1   1   0   x   x   x   x   512kb-motherboard (bank 0)
						 128kb-motherboard (bank 1)
*640kb*		 0   1   0   0   x   x   x   x   128kb-motherboard (bank 0)
						 512kb-motherboard (bank 1)
Position  Function
--------  --------
 1-3	   system memory configuration
 4	   64kx1 or 256kx1 DRAMs on the motherboard

	My question is, if you replace the soldered 64k chips with 256k
chips, can you access the memory above the 640k?

On the subject of add-on drives for the 6300+:
	In November I saw an early version of it *at AT&T* in New York at a
repair class.  It had a WD short board controller with a Seagate ST225
20 meg hard disk.  Need I say more?

On the subject of interleave factor:
	I recently set up a 6300 with a WD short board (WD1002S-WX2 and
the 'S' stands for short) and a NEC 5126 (I think the # is correct?) 20 meg
drive.  I used the firmware hard format at 0C800:5 with debug and the
default interleave of 3.  I ran Norton's disk test (DT /D) and it took
14:06 minutes.  I reformatted the drive with an interleave factor of 6 and
the same Norton test took 5:43 minutes!  I'm not sure what will happen
when I get to writing stuff on the inner cylinders of the disk but that
difference sure is impressive, and noticeable in applications.

				... Jeff

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