Electric VLSI Design System User's Manual

Chapter 1: Introduction

1-3: Requirements

Electric is written in the Java programming language and is distributed as a single ".jar" file, typically called "electric.jar". There are two variations on the ".jar" file: with or without source code. Either of these files can run Electric, but the one with source code is larger because it also has all of the Java code.

Electric requires Java version 1.5 or later from Sun Microsystems. It can also run with Apache Harmony. However, it does not run properly on some open-source implementations of Java, including the version shipped on Fedora Core systems. You will have to reinstall Java from Sun or Apache in such cases.

If you extract the source code from the ".jar" file and wish to build Electric, note that there are some Macintosh vs. non-Macintosh issues to consider.

Build on a Macintosh The easiest thing to do is to remove references to "AppleJavaExtensions.jar" from the Ant script (build.xml). This package is a collection of "stubs" to replace Macintosh functions that are unavailable elsewhere. You can also build a native "App" by running the "mac-app" Ant script. This script makes use of files in the "packaging" folder. Macintosh computers must be running OS 10.3 or later.
Build on non-Macintosh If you are building Electric on and for a non-Macintosh platform, remove references to "AppleJavaExtensions.jar" from the Ant script (build.xml). Also, remove the module "com.sun.electric.MacOSXInterface.java". It is sufficient to delete this module, because Electric automatically detects its presence and is able to run without it.
Build on non-Macintosh, to run on all platforms To build Electric so that it can run on all platforms, Macintosh and other, you will need to keep the module "com.sun.electric.MacOSXInterface.java". However, in order to build it, you will need the stub package "AppleJavaExtensions.jar". The package can be downloaded from Apple at http://developer.apple.com/samplecode/AppleJavaExtensions/index.html.

Memory Control

One problem with Java is that the Java Virtual Machine has a memory limit. This limit prevents programs from growing too large. However, it prevents large circuits from being edited.

If Electric runs out of memory, you can request more. To do this, use General Preferences (in menu File / Preferences..., "General" section, "General" tab). At the bottom of the dialog are two memory limit fields, for heap space and permanent space. Changes to these values take effect when you next run Electric.

The heap space limit is the most important because increasing it will offer much more circuitry capacity. Note that 32-bit JVMs can only grow so far. On 32-bit Windows systems you should not set it above 1500 (1.5 Gigabytes). On 32-bit Linux or Macintosh system, you should not set it above 3600 (3.6 Gigabytes).

Permanent space is an additional section of memory that can be insufficiently small. For very large chips, a value of 200 or larger may enhance performance.

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