EZD for AMOS Installation Guide

Updated May 24, 1997

Introduction

EZD for AMOS allows various removable media drives to be used in a plug and play manner with the AMOS operating system. You can install and remove the EZ Drive without re-booting the system, allowing you to move the drive between systems or change cartridges without disturbing other users.

EZD for AMOS has been tested with AMOS 1.4 and all versions of AMOS 2. It is compatible with both the SASI/SCSI interfaces present on older Alpha Micro computers as well as the SCSI dispatcher interface found on more modern models. Systems using containing a SCSI-2 processor are able to take advantage of automatic read-ahead and write-behind caching for spectacular performance.

Loading the software

EZD for AMOS is distributed in a PC compatible ZIP file, so you'll need to move the files to AMOS after extracting them.

Using EZD

Using EZD is very simple. At the AMOS prompt, type:

EZD

You'll be shown a list of free SCSI addresses. Set the SCSI address switch on the drive to one of the free addresses shown and connect the SCSI cable to the drive. Press RETURN and the EZD logicals will appear.

You can now use the EZD logicals like any other AMOS disk.

If you want to disconnect the EZ Drive or change cartridges, type:

EZD/U

The EZD program will then flush any pending writes out to the cartridge and then remove EZD from the system. It's really that simple.

Making EZD part of your system

EZD is able to install and de-install without re-booting the system by using some very complex software techniques. Without modifying the INI file and re-booting, it is not possible to get multi-user access to the EZD logicals. This means that the job running the EZD program will be the only one able to access the EZD.

To allow multi-user access to EZD, you must add the EZD driver to system memory and re-boot. To do this, type:

LOG SYS:
VUE AMOS32.INI (or AMOSL.INI)

Find the line that reads SYSTEM by itself and insert the following on the line before it:

SYSTEM EZD.DVR[1,6]

Re-boot either using MONTST or by pressing the reset button.

If you have a SCSI-2 interface

Congratulations! You'll be able to take full advantage of the EZD and obtain fabulous performance. There is one thing you must watch out for though: Synchronous Transfers.

This new transfer mode, introduced in the SCSI-2 specification, can be slightly increase throughput on systems with a large number of disk drives connected to the same SCSI interface. It does this by setting a fixed transfer rate between the drive and the SCSI controller chip.

The problem arises if you power down the EZ Drive (which is synchronous transfer compatible) without re-booting the Alpha Micro. The next time the Alpha Micro attempts to communicate with the EZ Drive, it will use synchronous transfers but because the EZ Drive has been reset, it will revert to asynchronous mode, the power on default. This will cause the SCSI bus to hang and probably failure of the entire system.

To solve this problem, you must be either very careful about using EZD or disable synchronous transfers by adding the /N switch to the SCZDSP line in your INI file and rebooting the system. For example:

SCZDSP SCZ190/N
or
SCZDSP SCZRR/N

Formatting cartridges for use with AMOS

Although Alpha Micro's FMTSCZ program can format cartridges, the size of the logicals on the disk probably won't be correct if you use this utilty. We recommend using FMTSC2 which is available from Alpha Micro.

This utility will get the best size for traditional logicals and is much easier to use than FMTSCZ.

General Dos and Don'ts

The EZ Drive is small and portable and the cartridges are very rugged, however, because of it's nature, we recommend the following:

Product Support

As EZD for AMOS is free software, it is unsupported.