Hardware

The Silicon hard disk designed by Andrew Gregory delivers a 128K  battery backed up disk drive to DOS65, as third drive 2:. It is empty after a boot of the system by formatting by a program at startup.
Extremely useful to use for utilities and fast disk access for temporary files, leaving drive 0: and 1: free to switch floppies. Ofcourse all is lost on the silicon drive if the battery backup is not active.

The hardware consists of 4x 62256 SRAMs with glue logic and latches to hardware addresses latch at $FFF1 and disc paged memory at $E200. he hardware of the disc consists of 256 blocks of 512 bytes.
A block is selected by writing its number to the block latch at $FFF1. This also activates the card.
The card can be deactivated leaving the 512 bytes of memory available to other cards by writing anything to $FFF0.

Software

The following program formats a silicon disk, to be used at boot in LOGIN.COM, note that this destroys the contents!

 ttl  Silicon disc formatter V0.1               
 
	pag	66
;
;files		silicon.MAC
;
;last modified	20th February 1988
;
;program	Silicon
;
;function	Verify and format silicon disc
;		This version for 128K discs
;
;usage		SIlicon -AVY
;
;by		Andrew Gregory
;
;
;Notes: The hardware of the disc consists of 256 blocks
;of 512 bytes. A block is selected by writing its number
;to the block latch at $fff1. This also activates the card.
;The card can be deactivated leaving the 512 bytes of memory
;available to other cards by writing anything to $fff0
;
;The disc is configured to 16 sectors by 32 tracks 
;in software. (Performed by setup routine in 
;dospatch.bin).
;
;DOS65 routines and variables
	lib	dvar.mac
	opt	lis
;
;interface addresses
;
;hardware addresses
latch	equ	$FFF1	paging latch
silic	equ	$E200	disc paged memory
;
;zero page workspace
;
	org	$80
opt1	        res	1
;
	org	$A000
	jmp	begin
;
;give help reply
	fcc	$C8,$C5,$CC,$D0
	fcc	$EA,$EA,$EA
	fcc	'128K SILICON DISC FORMATTER v0.1'
	fcc	'\rSyntax:  SILicon -AVY'
	fcc	'\rOptions  -A : Close all files if error'
	fcc	'\r         -V : Verify before formatting'
	fcc	'\r         -Y : Do not ask for '
        fcc     'permission first',0
;
;tables
;point to each fcb+0 (indicates if file open)
fcb0	fcc 0,24,48,72,96,120
;point to each fcb+13 (indicates drive/dir)
fcb13	fcc 13,37,61,85,109,133
;
begin	php			save flags
;
	jsr	sopt		get options
	fcc	'AYV',0
	bcc	1.f		branch if OK
er1	jsr	print
	fcc	'Illegal -options',0
exitcr	jsr	crlf
exit	plp
	rts			return to DOS65
;
er2	jsr	print
	fcc	'*** File(s) open on drive 2',0
	jmp	err
;
;Check that all files to this drive are closed:
1	ldx	#5		six files
3	ldy	fcb0,x
	lda	varo,y		file number x+4 open?
	beq	2.f		branch if no
	ldy	fcb13,x
	lda	varo,y
	and	#3		discard sub-dir
	cmp	#2		drive 2?
	beq	er2		error if yes
2	dex
	bpl	3.b
;
	lda	opt		Get options
	asla
	sta	opt1
	asl	opt1		Permission needed?
	bcs	1.f		branch if no
	jsr	print
	fcc	'Destroy silicon disc? Y/N ',0
	cli
	jsr	in		get input
	jsr	loupch
	cmp	#'Y
	bne	exitcr		abort if no
	jsr	crlf
;
1	lda	#0		try to find out if
	tay			card plugged in.
	dey
	sta	latch		First block
	sta	silic
	cmp	silic
	bne	0.f
	sty	silic
	cpy	silic
	beq	2.f
0	jsr	print
	fcc	'*** Silicon disc not working',0
;
err	lda	opt		-A option
	bpl	0.f
	jsr	sync		close all files
0	jmp	exitcr
;
2	sta	silic+$100	second block
	cmp	silic+$100
	bne	0.b
	sty	silic+$100
	cpy	silic+$100
	bne	0.b
1	asl	opt1		Verification?
	bcs	4.f		Branch if yes
	jmp	9.f
;
;
;fill all memory with $00
4	tax
3	stx	latch
	tay
2	sta	silic,y
	sta	silic+$100,y	second page
	iny
	bne	2.b
	inx
	bne	3.b
;
;check all 0's and fill with $ff
	tax
3	stx	latch
	ldy	#0
2	lda	silic,y
	bne	badmem1
	lda	#$ff
	sta	silic,y
	cmp	silic,y
	bne	badmem1
        lda	silic+$100,y
	bne	badmem2
	lda	#$ff
	sta	silic+$100,y
	cmp	silic+$100,y
	bne	badmem2
	iny
	bne	2.b
	inx
	bne	3.b
;
	beq	9.f
;
;Error message and return.
badmem1	sec
	bcs	1.f
badmem2	clc
1	txa
	php
	jsr	print
	fcc	'*** Error at block=',0
	tay
	pha
	txa
	jsr	hexout
	jsr	print
	fcc	'  address=',0
	pla
	plp
	bcc	1.f
	jsr	print
	fcc	'E2',0
	jmp	2.f
1	jsr	print
	fcc	'E3',0
2	jsr	hexout
	jsr	crlf
	jmp	err
;
;
;Copy syssec to track 0 sector 1
9	ldy	#0
	sty	latch
1	lda	sysdat,y
	sta	silic,y
	iny
	bne	1.b
;
;set creation and modification dates
	ldx	#3
6	lda	date,x
	sta	silic+$58,x
	sta	silic+$5C,x
	dex
	bpl	6.b
;
;fill directory sector with zeros
;track 0 sector 3.
	tya
	ldx	#32
	stx	latch
2	sta	silic,y
	iny
	bne	2.b
	plp
	rts
;
;system sector. 256 bytes.
sysdat	fcc	'0123456789ABCDEF'	stab. Not used.
        fcc	'0123456789ABCDEF'	
	fcc	$80	s.mode	indicate stab not used
	fcc	32	s.mtrk	number of tracks
	fcc	16	s.mcil	sectors/track
	fcc	16	s.msec	single-sided
	fcc	$ff,$ff,$ff,$ff
	fcc	1	s.acnt	1 sector per bit
	fcc	1	s.sht	one shift -> bmap pos.
	fcc	0	s.tbas	first tsl track
	fcc	$ff	s.tbam
	fcc	1	s.dbas	first data track
	fcc	0,0,0	reserved
	fcc	0,0	s.boot	Not bootable
;
;			Subdirectory track-sector addresses
	fcc	0,0	A
	fcc	0,0	B
	fcc	0,0	C
	fcc	0,0	D
	fcc	0,0	E
	fcc	0,0	F
	fcc	0,0	G
;
;disc name. Exactly 24 characters.
	fcc	'Silicon disc'
	fcc	0,0,0,0
        fcc     0,0,0,0
        fcc     0,0,0,0
;
	fcc	0,0,0,0  s.cdat	creation date
	fcc	0,0,0,0	 s.mdat	modification date
;
;bitmap follows. 64 bytes signifigant. Unused bytes
;must all be zero. Each bit represents occupancy
;of one sector.
	fcc	$fa,$ff,$ff,$ff,$ff,$ff,$ff,$ff
	fcc	$ff,$ff,$ff,$ff,$ff,$ff,$ff,$ff
	fcc	$ff,$ff,$ff,$ff,$ff,$ff,$ff,$ff
	fcc	$ff,$ff,$ff,$ff,$ff,$ff,$ff,$ff
	fcc	$ff,$ff,$ff,$ff,$ff,$ff,$ff,$ff
	fcc	$ff,$ff,$ff,$ff,$ff,$ff,$ff,$ff
	fcc	$ff,$ff,$ff,$ff,$ff,$ff,$ff,$ff
	fcc	$ff,$ff,$ff,$ff,$ff,$ff,$ff,$ff

	fcc	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
	fcc	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
	fcc	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
	fcc	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
	fcc	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
	fcc	0,0,0,0,0,0,0,0,0,0,0

 ttl "tp DOS65 Patch for silicon disc              %s             page %d"

	pag	66

;
;files		dospatch.MAC
;
;last modified	15th February 1988
;
;program	DOS65 patch for silicon disc
;
;function	replacement read /write routines
;
;by		Andrew Gregory
;		England
;
;Include the following statement near the beginning
;of your LOGIN.COM command:
;LOAD dospatch.bin
;
; *****************************************************
; *                                                   *
; *  You may have to assemble to a different address  *
; *  to suit your version of DOS65                    *
; *                                                   *
; *  These routines overwrite the existing routines   *
; *  without any spare bytes!                         *
; *                                                   *
; *****************************************************
;
;DOS65 routines and variables
	lib	dvar.mac
	opt	lis
;
;64K Virtual disc configured as 16 tracks by 16 sectors.
;128K disc configured as 32 tracks by 16 sectors.
;
;hardware addresses
silic	equ	$e200		disc memory
latch	equ	$fff1		disc page latch
disable	equ	$fff0		disable card address
;
;X=trk number. Y=sector number.
;
	org	$cee3
setup	sty	$aafd		(ytmp)
	bit	$aaf8		(ctype)
	fcc	$10,$17		bpl if floppy
	dey
	tya
	ldy	#4
2	pha
	txa
	lsra
	tax
	pla
	rola
	dey
	bne	2.b
	sty	disable		clear all devices
	sta	latch		select board and page
	ora	#$80		N=1
	clc
ret	rts
;
;
;64K drive (2 track): x=0
;128K drive (1 track): x=0 or x=1
;
	org	$ce4a
wvirt	sec			same as existing routine
rvirt	php			   "
	sei			   "
	ldy	#0
	txa
	beq	10.f		if track 0
;
0	bcc	2.f
	lda	[rwpoin],y	write
	sta	silic+$100,y
	bcs	3.f		always
2	lda	silic+$100,y	read
	sta	[rwpoin],y
3	iny
	bne	0.b
	beq	9.f
;
10	bcc	2.f
	lda	[rwpoin],y	write
	sta	silic,y
	bcs	3.f		always
2	lda	silic,y		read
	sta	[rwpoin],y
3	iny
	bne	10.b
;
9	plp
	clc
	jmp	$ce2c		(rs9) Check this!