Setup and Benchmarks of Several ESDI Hard Disks and Controller Cards

To setup an ESDI storage system you will configure the drive first, than configure the controller card, and at last you do the cabling.

Disk Drives and General Drive Setup

Fifteen drives are available and will be tested. Since the formatted capacity depends on the controller card used, unformatted capacity is given.

Manufacturer	Model	Form Factor	Unformatted Capacity (Megabyte)
NEC	D3661	3,5" half height	134.5
NEC	D5655	5,25" half height	179.8
IBM	0667-85	5,25" full height	85
Micropolis	1654	5,25" half height	178.4
Micropolis	1558	5,25" full height	382.3
Seagate	ST-1111E	3,5" half height	111
Imprimis	94186-383	5,25" full height	383

Manufacturer	Model	Form Factor	Unformatted Capacity (Megabyte)
Micropolis	1664	5,25" half height	389.3
Micropolis	1568	5,25" full height	765
Seagate	ST-2383E	5,25" half height	383
Maxtor	XT-8760E	5,25" full height	768.9

Manufacturer	Model	Form Factor	Unformatted Capacity (Megabyte)	Click on Picture to Magnify
Hewlett Packard	HP 97548E	5,25" full height	795.9
Hitachi	DK515	5,25" full height	780

Manufacturer	Model	Form Factor	Unformatted Capacity (Megabyte)	Click on Picture to Magnify
Micropolis	1538	5,25" full height	1,043

Manufacturer	Model	Form Factor	Unformatted Capacity (Megabyte)	Click on Picture to Magnify
Hitachi	DK516-15	5,25" full height	1,538

ESDI hard drives demand some configuration work, which is done through jumper blocks or dip switches.

Termination
First of all, the drive at the end of the 34pin control cable has to terminate the ESDI bus. Usually this is done by a resistor IC, which is socketed on the drive's printed circuit board (PCB). All other drives at the control cable have the resistor IC removed.

Drive Address
Every drive connected at the 34pin control cable needs a unique drive address. ESDI drives are numbered from 1 to 7. Most controller cards support two drives, very few four drives. Sometimes the controller manual speaks of drive 0 and drive 1, which - in case of ESDI - always means drive 1 and drive 2.
There are 34pin controller cables with a twist between pin 26 and 28. If you use such a cable, the drive before and the drive behind the twist should be configured as drive 2. Now the position of the drive on the 34pin drive control cable determines the drive address. If the drive is connected behind the twist at the end of the cable, it's drive address is 1. If the drive is connected between the twist and the controller, it's drive address is 2.

Drive Hard Sectored or Controller Soft Sectored?
Generally drives should be configured for hard sector mode, with 36 sectors per track (spt) for 10MHz drives and 54spt for 15MHz drives, thus giving the largest storage space and the highest data throughput possible.
Some controller cards do not support 36/54spt with an 1-1 interleave. Some of these cards ignore the drive's hard sector configuration and instead enforce a soft-sectored low-level-format with 35/53spt. Unfortunately, there are controller cards, which demand hard sector mode, but will not function properly or will function with poor performance, if the user chooses a sectors per track value to high. Hard drives from 20MHz data rate upwards are hard sector formatted only.

Miscellaneous Options
The hard disk should be configured for spin up at power on. Write protection should be disabled.

Last not Least: Grounding of the Disk Drives
All drives but one work when the chassis is grounded to the drive support structure.
In the IBM PS/2 Model 80 environment the drive's chassis has to be divided electronically from the support structure. Use plastic mounting rails for that reason. If the drive's hard disk assembly (HDA) has a grounding connection like e.g. the IBM 0667-85 disk drive, use it to ground the HDA against the support structure.

For the specific drive setup consult the resources page and look for the drive reference. Do not change other than the above mentioned drive pcb jumper settings, if they are in the manufacturer's standard position.