I would love to get my hands on one of these again, will even consider a non-working unit. I owned one back in the 80's purchased directly from ICT; a 20 MB model. Used for a BBS system. When it died I gave it to a friend with more electronic expertise but things happen and I haven't seen it since. :gråta:
Will also take any information on this drive that anyone would care to share. Including documentation, pictures of the internals, or ROM images. Info on the Internet is scarce.
Thanks for listening.
Eric
I've been keeping an eye out for an ICT Data Chief or Mini Chief for over a year now, and so far I haven't found one... :(
You may find this thread (http://landover.no-ip.com/128/viewtopic.php?id=1307) interesting for further information on these drives. :)
-Andrew
Thanks for the info Andrew. I had seen that thread and I've even contacted Tom who had the www.datachief.org web site. He's moving it to another server so hopefully all that info will be available soon. It does seem these drive are fairly rare nowadays. If I can't find one I'm hoping with enough information I can clone one. Here's some info I've been able to find so far:
1. People have reported the Mini Chief had a Segate ST225 20 megabyte MFM hard drive
2. Also reported was it used a Western Digital 8-bit WD1002A-WX1 controller. This controller has a built-in low-level format program. To enter the program run the DEBUG utility supplied with DOS and at the prompt enter: G=C800:5.
3. Jim Brain reported ICT ripped out the internal power supply. Must be how they made room for the harddrive and controller. I didn't remember mine having an external power supply but if you look at this picture here I guess that is the power supply sitting on top of the Mini Chief http://www.zimmers.net/anonftp/pub/cbm/pictures/gpage1/20.jpg
4. Here's the best info I've found so far, this was found in an archive from the www.datachief.org site:
The "CIA #3" shown in the schematic is actually the only CIA (MOS 6526A)
chip used in the 1571 drive, U20 on my 1571 pcb. The stock 1571 circuitry
only uses a samll part of this CIA chip (the SP register at $400C); the
other two 8-bit data ports are wasted ($4000-4001). The ICT uses these two
ports to control an 8-bit western digital hard drive card designed for the
PC-XT, "classic 8-bit bus". The card address is hard wired active (eg. pins
A10-A31 are wired so that the card is always on...) Port A of U20 ($4000)
is used to read/write the data to the hard drive card data bus. Port B of
U20 ($4001) is used to select the card address (bits 0, 1, & 2) and read/
write status of data bus (bits 3 & 4) and reset the hard drive card (bit 5).
Bits 6 & 7 are unused...
The ICT rom also needs an extra memory buffer- in this case, an 8kB 6264
static ram chip. The chip is mapped at $5000-6FFF but $7000-7FFF is a
mirror image of $5000-5FFF (i.e. any data writen to $7000 will replace data
at $5000...) The static ram is piggy-backed on the 6116 ram (U3) already
used by the 1571 circuitry ($0000-07FF). The pin-outs almost match exactly
except the 6264 has an extra four pins. Pinouts shown below. I have not
yet disassembled the ICT rom so information is a bit vague but I suspect
there are several versions, each matched to the WD card used, as different
cards seem to not work with the data chief I have... The rom I have
included is v7.12 and it controlls a western digital card (WD1002A-WX1).
Any MFM hard drives (20meg max.) you plan to use with the controller need
to be low-level formated on an PC-XT using the FDISK.COM program or an
equivelent program such as DISK MANAGER by on-track technologies. The
most common drive used with the ICT is the seagate ST-225 MFM hard drive but
other MFM drives will work; I have used a rodime RO202E and it worked 100%
but it is a full height 5.25" 20meg. so the lights about dim when it powers
on... Anyway, you will need to partition the drive on the XT but you don't
need to format the drive as a logical DOS drive (eg. FORMAT C:) -This MUST
be done on a PC-XT as the PC-AT's use different sector mapping and the
low-level formats are incompatable (a MFM formated XT drive can't be
read/writen to on an AT without reformating...) and the ICT software has no
low-level format routines... I supose you could write your own but you
would need good documentation on the WD card used in your ICT. For me, it
is easier to pull the XT out of the closet and power it up to format new/
reformat old drives... That's about the only use that XT has (smirk).
Once the drive has been low-level formatted it is ready to install the card/
drive into the ICT and once powered on the access light should be on and
as the hard drives power up to speed the 1571 pcb will hold the serial bus
"busy" and after the hard drives initialize the access light will go out
and the 1571 will release the serial bus. (my drives/1571 pbc are installed
in an old XT case; with the XT motherboard removed it has two full-height
drive bays and a 5/12 volt power supply and plenty of room for the 1571 pcb,
WD card, and I have even thought of putting a c64 motherboard in it but
haven't as of yet...) Also, I need to mention the BOSS switch cause the
ICT "instructions" do a real piss-poor job of explaining its function-
The BOSS switch just toggles bit 3 of VIA #1 ($1801). This bit is monitored
by the ICT rom and when grounded (floppy setting) the ICT will power up as
a 1571 disk drive; when this bit is held high (hard drive setting) the
drive powers up with H001 (first partition) being accessed. The BOSS switch
is also used to move the "anchor" partition and can be used to move to any
partition from another (usually not back, though) but you can use the "HM2"
command to select the home partition and switch the BOSS to the floppy
position (H000) then move to any partition and as soon as you flip the BOSS
switch you will be moved from the current partition to the "home" partition.
Please note: the drive WILL NOT chain partitions in the floppy position so
if the chain command (HM4 SSS EEE) is not working then try flipping the
switch to the other position. If this sloves the problem you have the BOSS
in the "hard drive" position- label accordingly...
I have writen a few programs for ICT management but none support 1571 mode.
I plan to revise many of these programs and include 1571 mode and some more
neet stuff but as of now most of my ICT utilities are minimal. The one neet
program that really needs explaination is BKP & RSTR. These two programs
simply copy track 18, sector 1 to track 18, sector 18 (usually unused) and
back... This allows the first sector of the directory to be restored when/
if an accedential format is issued (the ICT only clears the BAM and 18,1
so all that is needed to "unformat" is to restore these two sectors...) This
feature can cause problems if not understood- The track 18,18 is not used
untill more than 120 files are saved to the disk so on very long directories
this program might cause problems. Also, the program only restores the last
backed up directory so if files have been changed/deleted since the last
back-up/restore the directory will be incorrect and may fail and the BAM is
not restored so after a restore you should verify the partition.
That said, if you have any other questions I can answer you can reach me
on Canthro's Lair BBS, 407-895-5759, 24hr. 2400baud max. Orlando, FL. (#24)
Or on the internet, Email: radwar@orl.mindspring.com
Good luck,
Radioactive Warrior '96
CIA (U20) MOS6526A VIA (U4&9) MOS6522 SRAM (8kB) 6264-15
---\/--- ---\/--- ---\/---
GND-1 40-CNT GND-1 40-CA1 N/C-1 28-VCC
PA0-2 39-SP PA0-2 39-CA2 A12-2 27-R/*W
PA1-3 38-RS0 PA1-3 38-RS0 A7-3 26-N/C (A13)
PA2-4 37-RS1 PA2-4 37-RS1 A6-4 25-A8
PA3-5 36-RS2 PA3-5 36-RS2 A5-5 24-A9
PA4-6 35-RS3 PA4-6 35-RS3 A4-6 23-A11
PA5-7 34-*RES PA5-7 34-*RES A3-7 22-*OE
PA6-8 33-DB0 PA6-8 33-D0 A2-8 21-A10
PA7-9 32-DB1 PA7-9 32-D1 A1-9 20-*CE (*CS)
PB0-10 31-DB2 PB0-10 31-D2 A0-10 19-D7
PB1-11 30-DB3 PB1-11 30-D3 D0-11 18-D6
PB2-12 29-DB4 PB2-12 29-D4 D1-12 17-D5
PB3-13 28-DB5 PB3-13 28-D5 D2-13 16-D4
PB4-14 27-DB6 PB4-14 27-D6 GND-14 15-D3
PB5-15 26-DB7 PB5-15 26-D7 -------
PB6-16 25-PH2 PB6-16 25-PH2
PB7-17 24-*FLG PB7-17 24-CS1
*PC-18 23-*CS CB1-18 23-*CS2
TOD-19 22-R/*W CB2-19 22-R/*W
VCC-20 21-*IRQ VCC-20 21-*IRQ
-------- --------
SRAM (2kB, U3) 6116-4 74LS42 (piggy-back over another 74LSxx chip)
---\/--- -\/-
A7-1 24-VCC Q0-1 16-VCC
A6-2 23-A8 Q1-2 15-D0
A5-3 22-A9 Q2-3 14-D1
A4-4 21-*WE Q3-4 13-D2
A3-5 20-*OE Q4-5 12-D3
A2-6 19-A10 Q5-6 11-Q9
A1-7 18-*CE Q6-7 10-Q8
A0-8 17-D7 GND-8 9-Q7
D0-9 16-D6 ----
D1-10 15-D5
D2-11 14-D4
GND-12 13-D3
Quote from: pearsoe3. Jim Brain reported ICT ripped out the internal power supply. Must be how they made room for the harddrive and controller. I didn't remember mine having an external power supply but if you look at this picture here I guess that is the power supply sitting on top of the Mini Chief http://www.zimmers.net/anonftp/pub/cbm/pictures/gpage1/20.jpg
The photo description on this page (http://www.zimmers.net/anonftp/pub/cbm/pictures/gpage1/) says:
"Hard drives: I.C.T. Data Chief & Mini Chief (with power supply), Lt Kernal with multiplexer and host adaptor & cable."
(http://www.zimmers.net/anonftp/pub/cbm/pictures/gpage1/t/20.jpg)
So yes, it looks like that's the power supply. :)
-Andrew
Sounds like the Mini-Chief was a VERY clever hack!