ARXE support information

This page contains information related to the SCSI side of the ARXE High density/SCSI cards - I wasn't responsible for the HD software and as such have no information on it. Basically, this is all the support there is for the card nowadays.

There are several sections to this page:

Hardware

The card uses a NCR53c94 SCSI controller, or equivalent (Emulex ESP/FAS216, AMD 53c94, etc). On an ARM3, 8Mhz bus machine, transfer rates can peak at over 3Mb/second. Both internal (50w IDC) and external (50w full-size centronics) connectors are provided. Driver software is supplied on the on-board ROM. The high density floppy interface onboard uses an Intel 82077 controller - however, as I said above, I didn't write the code for that bit and so I have no idea about any of it!

Onboard termination is provided, and is fused - a common problem with card (*devices list either hangs or zips past too quickly) is due to the fuse blowing (FS1 on circuit board, next to the SCSI connectors). If it blows, this should be replaced with a 1A fuse for continued protection.

Information on link settings

Software/firmware

The SCSIformat programcan be found here.
The latest known versions of the firmware modules are here. If softloading the modules, they should be loaded in the order: SCSIdrive, SCSIfs, SCSIfiler - and they should be loaded before the desktop is started.

Docs

The Using SCSIform section from the manual.

Using SCSIForm

All cards and drives supplied by The Serial Port, are tested and pre-configured before shipping. Thus if you ordered both your card and SCSI drive from The Serial Port, you will not need to run this program, unless you are adding additional devices or need to modify your system for some other reason. The main usage for SCSIForm is to allow you to add, remove and modify SCSI devices as well as actually format SCSI drives.

NOTE: Please note incorrect usage of this program can result in loss of data, so you must be very careful when using this program!!

The SCSI card has been designed such that all configuration options are stored on the card itself in an EEPROM, rather than the computers CMOS memory. This provides two major advantages. Firstly accidental corruption of the CMOS memory does not affect the SCSI setting and secondly if the card is moved, then the card does not need to be reconfigured when installed in another machine, as the configuration settings are taken with it. Thus if you purchased a drive and card from The Serial Port, the card will be already configured for the drive.

SCSIForm Options

SCSIForm provides the following options:

[S]can SCSI bus for devices When used this will scan the SCSI bus and print a list of the devices visible to the interface card. The information printed will be in the following format:

Device Type   Capacity Vendor      Product Revision

0      Direct 100M     Seagate     ST1052  234

7      Host            Serial Port 16-bit  SCSI/HD 1.00

The [S]can options will display the following information:

Device Is the SCSI ID Type Indicates the nature of the SCSI device

Capacity Will indicate storage capacity for storage devices such as hard drives

Vendor Device manufacturer

Product Device model number

Revision Device version

[A]dd a device to EEPROM This allows a device to be added to the system. A series of questions will be displayed to which you need to enter the correct responses in order to correctly add a SCSI device.

The questions are:

SCSI ID A value 0-6, use scan to determine the device ID‘s. Please note that no two drives should have the same ID.

LUN Always 0 for hard disks, unless again you are partitioning a hard drive

Prevent/Allow Removal No for hard disks, Yes for removable drives Stop drive on dismount No for most modern hard disks, Yes for Syquest etc

Start drive on mount No for most modern hard disks, Yes for Syquest etc

Reserve/release drive No for most systems, yes if you have multiple hosts Lock drive on mount No for most systems, yes if you have multiple hosts

Write protect device? No unless you want to write protect your hard disk? This option is useful for schools. Partition a drive into 2 sections, keep all the applications on one drive and then write protect it. Thus preventing accidental or deliberate deletion and alterations of files and applications. The other drive can be used as a works disk.

Use Poll Changed No for hard disks, used to detect change of media with removable media such as Syquests, etc.

Partition Start OffSet 0, for all but the largest of drives. This is used to partition a large drive (>512Mb) into separate smaller, drives. For example, if you had a 660Mb drive you could set up drive 4 as per normal, then set up drive 5 with a partition offset of 512. Note that if you use the format command, all partitions will be erased.

[E]dit device flags Allows device flags such as start/stop/write protect etc as shown above to be edited for a previously added SCSI device.

[L]ow level device format This option should never really be used, as performing a high level format is usually sufficient, as most SCSI devices are formatted before leaving the factory. You may need to use this option if you have an old drive. Please note that the formatting process can be quite time consuming. The time taken being dependent on the size and speed of the drive.

[C]hange system settings Allows various options to be set that effect all SCSI devices:

SCSI Host ID 7 (Should not be changed)

Bus reset on hard break Yes

Bus reset on soft break Yes

Default device 4 (for a single hard disk)

Drive wait on boot up 20 secs. Allows the time to be specified that that SCSI interface will wait before trying to access the SCSI drive. This delay is required as most hard drives require approx. 15 to 25 seconds spin up time when first powered on.

Directory Cache Size (16K) See Manual for further details

[R]emove a device from EEPROM Remove lets you remove the last device attached to the system from the configuration held in the EEPROM.

[H]igh Level Format a Device This initialises a SCSI device so that it is suitable for use with RISC OS. Please note this will result in the loss of all information the the specified drive. Be very careful and ensure that you enter the correct device number when initialising. You will be asked to enter the size of the partition. If you wish to use the entire disk simply hit return, otherwise enter the number of megabytes to be allocated (refer to the Partition Start Offset option for further details). The program will ask you twice to make sure you are certain before initialising a device.

[Q]uit Quit and exit back to the desktop

NOTE: Some users have tried to add CDROM drives to their systems and find that the [A]dd media options recognises the device, but does not permit it to be added. The reason for this is that the CDFS software has it's own configuration options - refer to the CDFS section of this manual.

Link information for ARXE card

|>LinkInfo
|
The Alpha Card is fitted with several link pins these should not be changed under any 
circumstances, unless you know exactly what you are doing.

Links    Position         Purpose

PL3        Set           Terminator Power, this should always be set
                         and is part of the SCSI spec. Most Acorn SCSI
                         devices do not use this feature.
PL4        Set           A15 on eprom (pin 31 of socket)
PL5      Left Link       +5 volts left/A17 on eprom right (pin 30 of socket)
PL6      Unlinked        A18 on eprom (pin 3 socket)
PL7      Left Link       82077 ident pin low left/high right
PL9      Left Link       82077 drv2 pin low left/high right
PL14     right link      PL13 drive 0 left/drive 1 right
PL15     Unlinked        SCSI FIQ left/IRQ right

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This page is maintained by altman@cryton.demon.co.uk