Overview

sysvars is a small CLI tool for the Amiga that creates several environment variables holding valuable system information. These variables can be used, for example, in the startup-sequence to enable/disable certain patches, assigns, and so on.

Currently, the following variables are supported: <a name="overview_table"></a> |Variable|Availability|Description |--------------|------------------------------------------|------------------------------------------ | $CPU | always | installed CPU, for example 68030 (68080 is supported, but see limitations) | $FPU | if CPU ≥ 68020 | installed FPU, one of 68881, 68882, internal, or empty for LC/EC 040 and 060 CPUs where no FPU is available (see limitations) | $Chipset | always | installed graphics chipset, one of OCS, ECS, AGA, SAGA | $VFreq | always | vertical frequency of the native display, can be either 50 (PAL 50Hz) or 60 (NTSC 60Hz) | $TotalChipRam | always | total amount of Chip RAM installed (in KB) | $TotalFastRam | always | total amount of real Fast[^1] RAM installed (in KB) | $TotalSlowRam | if present | total amount of Slow[^1] RAM installed (in KB) | $TotalRam | always | Sum of Chip, Fast and Slow RAM for convenience (in KB) | $SlowRamFirst | see description | The variable is set to 1 if Slow RAM is first to be allocated as non-Chip RAM[^2], otherwise this variable is unavailable | $KickVer & $KickRev | always | Kickstart version and revision (see limitations) | $BSDSockLib, $BSDSockLibVer, $BSDSockLibRev | if present | ID, version and revision of bsdsocket.library | $UAEMajor, $UAEMinor, $UAERev | if detected | major, minor version and revision of UAE detected (see limitations) | $VampireType | if CPU = 68080 | type of vampire installed, for example "V2_600", or "V4_Standalone" | $VampireCoreRev | if CPU = 68080 | core revision of the currently flashed firmware .jic file[^3] | $VampireClockMult | if CPU = 68080 | vampire clock multiplier

Requirements

The tool works best with Amiga OS 2.0 or later. Here, it calls SetVar, which allows for local scope variables. Local scope is no limitation, because the workbench is also loaded in the scope of the startup-sequence. Another advantage is that it does not require ENV:. This means it can run very early, even before SetPatch.

However, for the purists, sysvars runs happily also on OS 1.3 and even down to OS 1.2. However, there are some limitations to consider (see limitations).

Installing

Copy sysvars (and the other tools if you need them) to your hard or floppy disk drive (e.g., in the c directory)
Add it to your startup-sequence or User-Startup
- For OS 2.0 or greater there is no issue to call sysvars very early, even before SetPatch
- For OS 1.3 and OS 1.2, you must ensure that ENV: exists prior running sysvars (see limitations)

Building

The source should build with VASM, AsmOne[^4], AsmTwo, AsmPro, PhxAss and asmotor

You can also compile this in VSCode using a nice VSCode plugin, a suitable configuration is included in the .vscode directory.

Testing

There is a filesystem structure in test/sysvars-test that can be used for testing in vscode (virtual filesystem) or on a bootable floppy/partition on a real Amiga. The actual test is the startup-sequence. It uses some other utilities described here.

There is a small script that creates such a bootable disk. Say, you have an empty floppy disk in DF1, then in a shell, just CD into the sysvars directory and enter execute CreateTestDisk df1

The test can also be executed from Workbench 1.3 and up by double-clicking the Sysvars icon (via IconX). To make the disk also boot with KS 1.2 and 1.3, some files from Workbench 1.3 are required, which cannot be distributed here. If you need this, just insert your Workbench 1.3 disk and double-click the Add OS 1.3 Support icon. Note that Workbench prior 1.3 cannot be used, due to the lack of support for environment variables.

Why such a Tool?

As many Amiga users, I have multiple Amigas, booting from flash memory. However, I do not want to maintain multiple operating system configurations. In the past, I have used several tools to branch during startup, which yielded a complex startup-sequence/user-startup and an extended boot time.

I wanted a small fast utility that gives me neat environment variables, so I can write something like this in the startup-sequence:

IF $CPU GE 68020 VAL
  MCP
ENDIF

IF $FPU EQ internal
  FastIEEE
ENDIF

Also, I always wanted to learn M68k assembler. After 30 years using an Amiga this was about time!

Aminet Distribution

The tool is also available in the Aminet and there is a script to ease the deployment. I try my best to keep both places in sync with GitHub being the ground truth. For each Aminet release, there should be a GitHub release and vice versa. This means everyone must first create a pull request following the Contribution Rules, before updating the original Aminet sysvars entry. To publish a custom version or a version from a branch/fork on Aminet witout a pull request, contributors should use a (slightly) different name to avoid overwriting the original entry.

Limitations and Disclaimer

As sysvars is optimized for speed, being compact and system friendly, it is not an elaborate H/W detection tool, such as WhichAmiga. This means that there might be system combinations, where sysvars gets it wrong. Some known limititaions are listed below. Anyway, you can always file a bug report, if you think that sysvars can be optimized.

Kickstart 1.3 and below

Sysvars currently detects CPUs above 68020 as 68020 and any FPUs as 68881.
Environment variables can only have global scope (i.e., they reside in ENV:). This means you must have ENV: mounted (e.g., to some folder on RAM:). This is not required for OS 2.0 and above.
Environment variables can only be used with the IF command (things like ECHO $CPU do not work. You must use IF $CPU GE 68010).

Kickstart 1.2

The native IF command does not support environment variables, but you can use the IF command from Workbench 1.3
Even with the Workbench 1.3 IF command, only EQ seems to work
$KickRev is set, but to an empty value

Slow RAM detection

RAM speed is not actually measured. Instead, it is assumed that any non-Chip RAM residing at $C0xxxx is actually Slow RAM. This is common for the Amiga 500s with a trapdoor expansion. Thus, if you have an expansion that actually maps real Fast RAM into the $C0 region, sysvars still consideres it to be Slow RAM.

UAE detection

UAE is detected via the uae.resource, which is only there if

a virtual hard drive or another UAE expansion is enabled
Kickstart is at least version 34 (OS 1.3) Thus, detection will fail on any floppy-only-unexpanded Amiga configurations and on anything with a ROM older than 1.3

The other Utilities

The following utilities are mainly intended to test sysvars, but could also be useful in other contexts.

`ksge36`

Quickly check if Kick ROM is at least version 36, which is the case for OS 2.0 or greater. If it detects a version below 36, it returns WARN (error code 5). It can be used (like it is in the sysvar test) to write startup-sequences that work for both OS 1.3 and OS2.0+, branching where needed.

`probevar`

A tool for all Amiga operating systems to quickly check for the existence of a local (OS 2.0 and up) or global (OS 1.3 and below) environment variable. It is similar to the Get command of OS 2.0 in that it returns SUCCESS (error code 0) If a variable is available and WARN (error code 5), if not. The difference is that

probevar does not write out the actual value, so you do not have to do a >NIL: to suppress it
probevar can be used in OS 1.3 and below (only there it queries global variables)

Why is this tool needed?

In the past, sysvars would set environment variables, such as $UAEMajor to an empty string if it did not detect UAE. So one could always use IF "$UAEMajor" EQ "". However, with the growing number of supported use cases and variables, the variable space became increasingly polluted. Therefore, I decided to only ever set variables, when the environment warrants for it (see the "Availability" column table at the top). Thus, if UAE is not detected, $UAEMajor will now not be available at all. So, code such as IF "$UAEMajor" EQ "" will no longer work as it would try to search for a global variable in ENV: interripting the boot process. Instead, you know use code such as

probevar UAEMajor
IF NOT WARN
;...

Future Plans/Known Bugs

The tool is already quite useable, but there are still some things missing, which I want to fix in future versions (no particular order):

Add $RTG variable to enable/disable stuff like FBlit or swap screen mode configurations

Sysvars

Install / Use

README