Configuring Adaptec 1542C card with XEN-LS II / XEN-PC

The 1540C/1542C are the latest versions of the card from Adaptec that have an on-board BIOS setup program called SCSISelect(TM). This program is run by entering Cntrl-A at boot-up if the BIOS is enabled on the card, or with a debug command such as g=dc00:6. There is a bank of 8 switches on the card that set some configuration parameters, but SCSISelect can override some of these. There are no other switches or jumpers. Follow the recommendations below for when to use the switches and SCSISelect and when to disable the BIOS.

Reference should be made to IPB 3144 which details patches required for fast machines with Unix and Xenix when using Adaptec 154x cards.

The card should function on its default settings of IRQ 11, DMA 5, I/O 330h, and BIOS address DC000 in the XEN-PC.

SCSI disks should be formatted and verified by using the SCSISelect BIOS utility prior to use.

XEN-LS II with SCO Unix 3.2v4 - SCSI root disk.

This configuration requires that there be no IDE drive present. Set the hard disk type to NONE within Setup and disable the hard disk controller - the latter has to be done also otherwise the SCO installation routine will still find an ST-506 type disk on IRQ 14 and try to prepare it; resulting in the installation exiting with a floating point error.

Set the switches for the 1542C as follows:-

At power up enter Cntrl-A to enter SCSISelect. Select the factory reset option to reset to a known start point. Change the IRQ to 9. All other settings remain at factory defaults.

At the boot: prompt from the SCO N1 floppy enter the following to boot the installation kernel with the Adaptec driver running on I/O address 330, IRQ 9, and DMA 5.:-

unix kernel.adapter=ad(0x330,0x9,0x5)

or, if an aborted or old installation exists on the drive:-

restart kernel.adapter=ad(0x330,0x9,0x5)

Once Unix is installed the link kit does not need modifying - the Adaptec driver is configured for the correct hardware settings.

XEN-LS II with SCO Unix 3.2v4 - IDE root disk.

Set the switches as above to enable the SCSISelect program to be run at boot up with Cntrl-A. Use SCSISelect to factory reset the card and then set it to IRQ 9 as above.

Now disable the card's BIOS by setting SW6, SW7, and SW8 to ON.

The sdevice.d/ad file does not require editing for use on IRQ 9 as does the spad file for the Adaptec 1510 card. The ad file has no definition for the IRQ.

XEN-LS II with SCO Xenix 2.3.4

The installation onto a SCSI root disk cannot be done because the SCO Xenix master floppies expect the Adaptec card to be on IRQ 11. This is not possible because of the clash with the security processor.

The card can be used with secondary SCSI disks and tape units when the standard IDE root disk is used. Install the card set for I/O address 330h and BIOS address DC00 and with the floppy controller disabled as in the table above. Use SCSISelect to factory reset the card and then set to IRQ 9. Disable the BIOS by setting SW 6,7, & 8 to ON.

Edit the ad0 line in /usr/sys/conf/master to reflect the card's setting of IRQ 9 by changing the 11th field from 33 to 31. An example entry follows:-

ad0     1  0337  014  ad0  0  34  34  1  5  31  0  0  0

From the /usr/sys/conf directory run the command ./configure -r to rebuild the link kit configuration files. Run ./link_xenix followed by ./hdinstall and then reboot.

To configure a SCSI tape drive XNX316 or APR316 should be installed. This will update the Adaptec drivers and is mandatory for the 525MB tape unit (See IPB 3119). Ensure also that the 525MB tape unit is strapped correctly as detailed in IPB 3131.

Without XNX/APR316 the following error will result when attempting to use the tape command:-

Once XNX/APR316 is installed the tape command options of status and reset will no longer exist for SCSI tape units. The tape command appears to forget the default of SCSI tape as defined in /etc/default/tape, our advice is to use the -s switch of the tape command to force SCSI tape usage. As an example, to retension a tape configured as rct0 use the command:-

tape -s reten

If the DDS tape unit is used a non eject device is created by remaking the node /dev/rct0 with 32 added to the minor number. For the normal SCSI tape unit on ID2 this node should have a major number of 36 and a minor number of 32. For new tapes in DDS units use the command 'tape -s erase' otherwise an error will result when trying to write.

For SCSI devices used on the Adaptec card with Xenix the major number is equal to the SCSI ID number plus 34 - ID0 = 34, ID1 = 35, ID2 = 36, etc.

To add support for SCSI disks use the mkdev hd command below as you must use the correct syntax. Running the command 'mkdev hd' will result in the system attempting to access a second ST506 drive:-

mkdev hd 0 2

Where the 0 denotes the SCSI ID of the hard disk and the 2 denotes the first Adaptec card when the boot disk is an ST506 drive.

The ID will be asked for despite the same number being given on the command line.

For accessing SCSI drives with fdisk the command syntax is as follows:-

fdisk -f <device> Where <device> is as in the table below:-

For accessing SCSI drives with divvy the command syntax is as follows:-

After installation of XNX/APR 316 the control device - /dev/xct0 - used by the tape command will have a minor number of 4.

XEN-PC with SCO Unix 3.2v4 or Xenix 2.3.4

The card should function on its default settings of IRQ 11, I/O address 330h, DMA 5 so should not present any problems. As stated above the SCO Xenix master floppies will expect the card on these settings and a SCSI boot disk installation should therefore work. Unix 3.2v4 will also install onto a SCSI boot disk with the card on these settings.

Unix device node major and minor numbers and device names for secondary drives and tape units will be identical to SCSI based MCA systems.

For SCO Xenix with a SCSI boot disk the fdisk syntax is as follows:-

fdisk -f <device> Where <device> is as in the table below:-

For Xenix SCSI tape unit configuration see the previous XEN-LS II section.

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