This Old Workbench Episode Nine

Copyright © 1998,2000 Dave S. Matthews

Tool Time: Beneath the Hood

A Tool of Beauty is a Joy Forever

This episode, I beginning a series on some powerful tools for working with your Amiga. This time it's peeking under the hood. Remember, when using power tools, safety first! These programs do many strange and wonderful things, and properly used, can make your Amiga an even finer testament to modern technology. Make sure you read (and follow) the accompanying documentation! As with all such power tools, blindly flailing about the interior of your Amiga can lead to unpredictable behavior, and nasty crashes, as well as feelings of fear, uncertainty and guilt.

Name: Executive
Short: UNIX-like process scheduler (V2.10)
Author: [email protected] (Petri Nordlund)
Version: 2.10
Aminet: util/misc/executive.lha
Requires: AmigaOS 2.04
Distribution: Shareware


Figure 1: Executive task scheduler
Figure 1: Executive task scheduler


Executive is one of the more sophisticated programs I've covered for the Amiga.

This program brings UNIX-like enhanced multitasking to the Amiga. Of course, the Amiga already has one of the best multitasking operating systems around, but what Executive gives the Amiga is process scheduling.

Before I get to Executive, a little background on the Amiga's OS might be in order. The Amiga's system of multitasking is known as preemptive, prioritized, round-robin. Preemptive means the OS controls the multitasking, and acts like a traffic cop, controlling the flow of the multiple programs, and preventing conflicts and traffic jams. Because of this multitasking OS, it may seem like the Amiga is running many different programs simultaneously, but, since the Amiga is not (yet) a parallel CPU system, it really can only do one thing at a time. Because the Amiga can only use one CPU at a time, when you run multiple programs on the Amiga, the OS must share the CPU between the programs. This is the round robin part. The OS, acting as a sort of traffic cop, lets a program run a bit, then moves permission to run to the next program, while the other programs wait. This normally happens so fast as to give the illusion of all the programs running simultaneously. The Amiga uses a system of task priorities to control the flow of program traffic. Each program is given a priority from -127 to 127 when it is run. The higher the priority, the more CPU usage the program gets. For most situations, this system works brilliantly, and the user never needs to mess with or even know about any program's priority. There are times, however, when more control of the situation is desired. For instance, say you need to raytrace a large animation project, one that might takes weeks of constant rendering. Because raytracing is so CPU intensive, you may find trying to run any other programs intolerably sluggish, and thus could well be without the use of your Amiga until the animation is finished rendering, for some a fate worse than death! Luckily, the Amiga does make provision for controlling this via Priority settings in the icon tool types, or the ChangeTaskPriority command. Unluckily, these are often inconvenient or ineffective.

This is where Executive comes in. Using the included scheduler to dynamically control task priorities, you can run that CPU hog of a raytracer to trace your masterpiece, and still be able to use the Amiga as if the raytracer were not running at all. Of course, to quote Heinlein- "there ain't no such thing as a free lunch!" When you use the scheduler to lower the priority of the raytracer, you are giving it less CPU time, so it will take longer to complete your picture or animation, but at least you will a usable Amiga for the duration.

Executive uses the tried and true client/server model. The server is the main program, which normally you would start in your WBStartup drawer. Clients are programs that use and support the server, such as the task manager, and the various CPU usage, task performance display utilities.

Executive includes a system og 'genies' and 'magic wands' to make scheduling different tasks easier, and to help with those programs which do not respond well to Executive's meddling.

Executive might seem rather daunting at first, and the truth is, most beginners will find it a tough go. However, the documentation for Executive includes much good information, general and technical, on multitasking, scheduling, and the Amiga's OS, and also features a helpful tutorial. Executive should prove very useful to those Amigans who do a lot of rendering, but still need to use their Amiga's for other tasks at the same time, or to those who just want more control over how their Amiga runs. See Figure 1 for a screenshot of Executive in action.

Name: SnoopDOS
Short: System monitor, many new features added.
Author: [email protected] (Eddy Carrol)
Version: 3.0
Aminet: util/moni/snoopdos30.lha
Requires: AmigaOS 2.04
Distribution: freeware


Figure 2:SnoopDOS looks behind the scenes
Figure 2:SnoopDOS looks behind the scenes


Have you ever tried to run a program, and it either crashes or just won't run at all, even though you know it ran before? Often, if a font or library was inadvertently deleted, the offending program will simply refuse to run or crash, without giving a hint about the reason. It would be nice to look behind the scenes and see what is going on with that program.

Enter Eddy Carroll's SnoopDOS. This handy utility has been around quite awhile, and while it won't help with every problem, I have used it to track down quite a few otherwise unsolved mysteries. SnoopDOS allows you to track all sorts of system functions, including Findtask, Lockscreen, OpenDevice, OpenFont, OpenLibrary, ReadTooltypes, SendRexx and a whole slew of other esoteric happenings. While many of these may not make any sense, and may not be of all that much use to any but the expert, some, such as the OpenFont, OpenLibrary, and ReadToolType can be indispensable to help track down program problems. See Figure 2 for a screenshot of SnoopDOS.

Name: SysInspector
Short: System monitor, with ClassAct GUI
Author: [email protected] (Eric Sauvageau)
Version: 1.1
Aminet: util/moni/SysInspector11.lha
Requires: AmigaOS 3.0+, ClassAct 2.0+,
latest version of ClassAct can be found at: ftp://ftp.warped.com/pub/amiga/classact/
Distribution: Shareware


Figure 3:SysInspector System Information
Figure 3: SysInspector System Information


SysInspector, by the author of newIcons 3.0, is another system monitor, though with a different focus than SnoopDOS. SysInspector lets you examine much of the internal workings of your Amiga's OS, such as Assigns, Commodities, Interrupts, Libraries, message ports, tasks and processes, screens and windows and the list goes on and on.

Above and beyond just looking under the hood, You can use SysInspector to tinker with the engine, as it were. Close orphaned windows left by crashed programs, selectively flush memory, send the break signal to programs, change a program priority, and more. See Figure 3 for SysInspector.

Name: SysSpeed
Short: Amiga System Speed Tester
Author: Torsten Bach
Version: 2.31
Aminet: util/moni/SSpd231.lha
Requires: AmigaOS 2.04, MUI 3.0+ (avail: util/libs/mui38usr.lha)
Distribution: freeware


Figure 4:SysSpeed rates my Amiga 1200
Figure 4:SysSpeed rates my Amiga 1200


Finally, when asked how fast my computer is, I normally respond, not fast enough! However, some times, a less vague answer might be helpful. SysSpeed is a program designed to test your Amiga speed, and compare it against other Amigas. This will give you some idea of your Amiga relative standing speedwise.

SysSpeed has various methods of calculating speed, including memory, drive, intuition (drawing windows and screens, etc.), graphics and others. It also has several 'real world' tests, using ADPro, CygnusED and other Amiga applications. See Figure four for SysSpeeds results on my 1200 68030@28MHz.


Tooled Out



Well, that's it for this episode, but there are loads of Amiga tools I haven't got to yet, so stay tuned.


 


This Old Workbench, Episode 09

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