Most controllers support only 2 hard drives under DOS. To sup-port additional drives, a software driver is required. If a driver for
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more drives exists, it is normally only available from the controller manufacturer. An exception to this are CSC's AK-47 and FC-64 boards that support 7 SCSI and 4 floppy drives without any drivers.
No BIOS Sign-On Banner
This is one of the most common installation problems. Check to see that your controller card BIOS does not overlap the memory areas used by other cards. In particular, watch for VGA and network cards.
If you still don't get a banner, check extended setup and make sure that the shadow RAM is disabled in the address range occupied by the controller BIOS.
Partition Can't Be Removed
If a drive is formatted with a 'non-dos' partition, FDISK will not delete it. The only solution is to erase the partition sector with a sec-tor edisec-tor or low-level format. Older versions of DOS (Le. 3.3) will not delete the larger partitions used by newer versions of DOS (Le. 6.0).
Later versions of DOS (Le. DOS 6.0) will delete partitions created in earlier (Le. DOS 3.3) versions of DOS. If a low level format is not in order, a program called "Zapdisk" is available from the CSC BBS at (408)541-8455 or www.corpsys.com to correct this. Zapdisk will remove all partition information without reformatting the entire drive.
Power Supply
Power supply problems frequently crop up in new drive installa-tions. Most hard disk drives require 5 volts + 5% and 12 volts + 5% at the drive connector. The power supplied to the drive must be clean and well regulated. All modern hard drives include circuitry which monitors the power supply voltages and shuts down the write cir-cuitry if the input power is too far out of range. Many drives won't even spin up if the power supply is too far off. If you suspect a power supply problem, check the voltages at the drive power supply con-nector while the drive spins up to speed and seeks.
SCSI Cabling
SCSI cables MUST be shielded for reliable operation. Many newer SCSI cables have individually twisted pairs for each signal line. If you
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Corporate Systems Center (408) 743·8787
can afford it, buy the better quality twisted pair variety. Avoid com-pletely unshielded SCSI cables at any cost.
SCSIID's
Each de:vice installed on the SCSI bus must have a unique and sep-arate ID number. Most SCSI controllers use ID #7, leaving the ID num-bers betwe:en 0 and 6 available for disk drives. For reasons unknown, some PC based tape drive software requires ID#7. If you have multi-ple DASD drives installed, most PC controllers win scan and boot from the lowest SCSI ID number. Exceptions to this are the Adaptec 1540 series which only boots from ID#O and the CSC FiashCache™64 which can be programmed to boot from any device.
SCSI TermintJrtion
A SCSI bus must be terminated at each physical end of the SCSI chain. Only two terminators per bus can be used. The devices at the physical ends of the cable must have terminators. All other devices on the SCSI chain (including the controller if it is not at the end of the chain) must have their terminators removed. If you are using external and internal SCSI devices on a PC controller, renlove the terminators from the controller card.
Shadow RAM
System memory should not be used to shadow controllers that are memory mapped. Controllers twhich are I/O mapped (i.e. ESDI cards) should be shadowed. System ROM should always be shadowed for performance.
System Hangs On Power Up
The foillowing are common installation errors which cause the sys-tem to hang on power up:
Improper BIOS base address (see above) Interrupt conflicts (see above)
Bus cotnpatibility jumper (try it both ways)
Reversed SCSI Cable (causes termination power short circuit)
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ThermQI Problems
Thermal problems are common in multiple hard drive installations and in situations where a hard or optical drive is not adequately cooled. Drives are mechanical devices and heat is their worst enemy.
As temperatures increase in a drive, the motor and bearings are sub-ject to increased wear.Always make sure a hard drive has a continuous flow of cooling air and adequate ventilation around it.
Twisted DQtQ CQbles
Twisted floppy and hard drive ribbon cables look suspiciously sim-ilar. Floppy cables have seven twisted conductors, and hard drive cables have five. Check the diagram in the previous chapter for a quick identification.
Won't Boot (DOS)
If your system has been formatted and won't boot DOS, check to see that the boot partition has been marked active in FDISK. Also make sure that the system (hidden) files have been correctly trans-ferred and that COMMAND. COM is present and matches the version of the hidden files. If your system was booting correctly but sudden-ly stopped, scan the boot sector for a virus.
Won't Boot (ESDI)
For new ESDI installations, make sure that translation and sparing modes have been set correctly. Also make sure that the system (hid-den) files have been correctly transferred and that COMMAND. COM is present and matches the version of the hidden files. If your system was booting correctly but suddenly stopped, scan the boot sector for a virus. Check FDISK and make sure the boot partition is marked active.
Won't Boot (IDE)
If you can use your IDE drive when booting from floppy but are unable to boot directly from the hard drive, check to see if your IDE drive requires "buffered interrupts". If it does, you may need to change a jumper on the controller card. Also make sure that the sys-tem (hidden) files have been correctly transferred and that
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MAND.CO~vl is present and matches the version of the hidden files. If your systern was booting correctly but suddenly stopped, scan the boot sector for a virus. Check FDISK and make sure the boot partition is marked active. Verify that the Master/Slave jumpers are correct. If your drive 'was booting on an older motherboard, but won't boot on a new one, check to see that the CMOS settings are identical.