User:Suenarmy

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D9090 Hard Drive (Manufactured by COMMODORE BUSINES MACHINES [CBM] )

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This was the first and last family of Hard Drive that Commodore made for both the Home & Business market. The Electronics are identical in a D9090 and D9060 unit, the only difference is the size of Hard Drive mechanism installed, and a jumper set on the DOS board to distinguish between 4 or 6 heads.

MODEL	TYPE	RPM	HEADS	ACTUAL SIZE	FORMATED SIZE	BLOCKS FREE
D9090	TANDON TM603S	3,600	6	9.6mb	7.52mb	29,162
D9060	TANDON TM602S	3,600	4	6.4mb	5.01mb	19,442

(on the D9090 25% of the Hard Disc is never used).

Internally the system was made up of Four major parts:- (1) CBM DOS 3.0 PCB, (2) SASI CONROLLER, (3) HARD DRIVE, (4) POWER SUPPLY

Input Voltages
100 Volts AC
117 Volts AC
220 Volts AC
240 Volts AC

POWER SUPPLY

4 Pin plug & cable - wiring and voltages follow world standard for large drive power cables, but colours not standard.

1 - 5 Volts

2 - Ground (black)

3 - Ground (black)

4 - 12 volts

CBM DOS 3.0 PCB

Ths DOS PCB was made up of several major electronic components: 3 x ROM's (Two for CBM DOS communication with host computer, One for SASI communications for Hard Drive formating- Track & Sector layout, 4 or 6 heads.) 4 or 6 heads is selectable only by a hardware jumper located on the front of the DOS PCB. 2 x MOS 6502 Microprocessors 2 x 6532 RIOT I/O Chip 1 x 6522 I/O chip Disk system buffer = 4k ( 8 x 2114 RAM chips) Commodore Device number selectable from 8 - 11 ( on IC 7H : 6532 )

CONNECTING 2 HARD DRIVES TO THE ONE (SASI) CONTROLLER

Capable of managing 2 x MFM Hard drive mechanisms, which is communicated to the user as two combined Directories, with one header number = 0 and the other header number = 1 Which is strange because most Commodore drives of this era required each seperate disk Directory to be called individually by a command LOAD"$",8,0 and LOAD"$",8,1 for the two drives that reside in Device 8. As a result it looks like the DOS was never fully completed by Commodore, which is evident when you save to the hard drive only to find that the two directories overlap for the one device and the number of blocks free is only displayed as if only one Hard drive is in use.

SASI CONROLLER

The main brain driving this controller is the AMD 'AM2910' ( A High-Performance 8-Bit Slice Microprogram Sequencer ) (The SASI Technology was invented by SHUGART who became SEAGATE (SASI, which eventually became standardised and known today as SCSI ) They also went on to create the company ADAPTEC.

HARD DRIVE

Internally the system had a transfer rate of 5.0 mb per second, from Hard Drive to CBM DOS 3.0 Controller PCB. (TANDON became WESTERN DIGITAL.)

HARD DISC (Inside the hard drive)

Cylanders = 153 (per hard disc) 6 head drive contains 3 x hard discs, 4 head drive contains 2 hard discs.

Sectors per Cylander = 192 (D9090)

Sectors per Cylander = 128 (D9060)

Sectors per track = 32

Bytes per sector = 256

IEEE 488 bus [24 wire parallel cable] http://en.wikipedia.org/wiki/IEEE_488 (Transfer rate 1.2 K per second from D9090/D9060 to Computer - 8 Data lines) D9090/D9060 Hard Drives can be daisy chained, the same as the comodore Serial bus used on the 1541, 1571, 1581 Family of floppy drives.

PET The D9090 & D9060 were designed for usage primarily on the Commodore PET Family of computers, but because these Metal cased family of machines were obsoleted by the VIC20 & COMMODORE 64, the greatest demand for these drives came from the biggest home computer user market in the world at the time, ie - The Commodore 64 User. As a result, Several companies built interfaces that effectively give a VIC-20 & Commodore 64/128 an IEEE-488 Port. Commodore created a VIC20 IEEE 488 cartridge : Model number : VIC1112

IEEE-488 (VIC-20)

VIC1112 cartridge (Internal view)

IEEE-488 (COMMODORE 64/128)

The Commodore 64 IEEE-488 Cartridges were made by various companies, but Commodore themselves never made one for the Commodore 64/128 family.

QUICKSILVER 64/128 by SKYLES ELECTRIC WORKS	COMPUTAPIX IEEE CArtridge	TECHNOFOR
QUICKSILVER-64/128 v2	C64-PLUS	VC40 Cartridge

Some other Interfaces, no Pictures available:-

E-LINK Serial ot IEEE Interface. (Contains 65C02, 6522 and 4K ROM)

Buscard II Interface. (Contains 6532, 6821 and 8K ROM, & 256 byte PROM)

COMMODORE 64 & 128 USAGE

The D9090 & D9060 Hard Drive was highly saught after in the early 1980's by the huge number of people using the Commodore 64 & Commodore 128 who wanted to taste the luxery of having all their Utilites & Games in one place, and being able to load these files/Games at high speed, with an overall loading speed 5 times faster than the standard drive that most people were using, Model : 1541 ( 664 BLOCKS FREE ) Where as a D9090 hard Drive has 29,162 BLOCKS FREE !!! Which is why many BBS's (Bulliten Board Systems) were set up on these hard drives because they could access information so fast and could hold so much information compared to the 1541 disk drive which could only access 170k on one side of one disk at one time. By the Late 1980's, the Commodore 64 had obsoleted all other Commodore 8-Bit machines mainly because of the sheer number of users world wide and also the market support from so many 3rd party software & hardware companies. As a result, the older IEEE-488 Disk Drives & Hard drives were being aquired by large numbers of C64 owners to connect to their computer using an IEEE-488 Interface. This has put pressure on the supply of these devices as now a days they are wanted by both Commodore 64/128 users and also needed by people using the PET family of machines, that these drives were specifically designed for.

PARTITIONS & SUB DIRECTORIES Due to the structure of the onboard DOS 3.0, there is only one main Partition which conatins the Directory and all files saved. There are no Sub Directories so eventually you run in to trouble when you type LOAD"$",8 and LIST , the Directory list fills the screen and then scrolls away. You can pause the Directory Listing as with any Commodore computer, but if you have 100 Files saved, then you have to wait some time until the Directory Listing reaches the bottom.

PRICE WHEN NEW The oldest Price list I found was titled "COMMODORE PRICE LIST 1-SEPTEMBER 1983"

D9060 Hard Disk Drive 5 Megabytes = $4648 (Australia), £1995 (UK)

D9090 Hard Disk Drive 7.5 Megabytes = $5813 (Australia), £2495 (UK)

INTERNALS EXPLAINED

Any 4 or 6 head MFM drive mechanism can be used as a replacement mechanism.

FORMATTING

D9090 (6 heads) Formatting takes 1 hour and 20 minutes !!! so be very very very very patient...

D9060 (4 heads) Formatting takes about 1 hour  !!! so again you need to be very patient...

SOFTWARE, DRIVERS & TECHNICAL SUPPORT

C64 based Software for Drive management, File transfers & Repair diagnosis is available from the SPACE_TAXI website. http://members.optusnet.com.au/vortex69/HARD_DRIVE-D9090/D9090.html

A program & cable exists which lets you use a common IBM compatible PC as a Virtual IEEE-488 Hard Drive, from here : http://www.baltissen.org/htm/cbmhd.htm

[edit] REFERENCES

1. The Commodore D9090/D9060 Users Guide.

2. The Commodore D9090/D9060 Workshop Repair manual.