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• functional specification
• specification of class clusters

Functional Specification

Functional specification is list of capabilities of RCOS.java

• simulated CPU is pcode machine with additions for interrupt handling (??) and paged memory
• CPU will carry out obvious steps in instruction execution cycle (instruction fetch, instruction execution, check for interrupts and handle interrupts)
• simulated disk is similar to RCOS disk however code will need to be modified to stay inline with new interrupt handling mechanism
• should support multiple disks
• terminal similar to RCOS including support for multiple terminals
• size of RAM will need to be increased
• NetworkCard simulation given time
• all hardware simulation belongs to a class Machine

• machine language is Pcode
• source language will be Pascal (hopefully full version) and possibly C++/C subset if appropriate compiler can be found/built
• some work will need to be done so that code and data (variables and stack) are placed into separate pages
• theoretically possible to provide a compiler that runs from within RCOS
• which implies the need for a shell (and editor??) that runs on RCOS

• graphical animation/representation of all OS elements (will include some representation of H/W elements)
• provide as much direct manipulation as possible
• ability to single step simulation at individual machine instruction, interrupts, OS events, quantum switches through various levels up to not at all
• ability for guided tours implies need to automate setup and running of system
• ability to use components of the animation/OS to demonstrate particular algorithms e.g. talking about CPU scheduling it would be nice to show just the context switching going on
• AnimationSupervisor is responsible for upkeep of main screen and for delivering messages between the various other animators

• keep statistics in much the same way as Nachos but provide graphical representation of stats for each execution and ways to compare (useful for experiementation)
• no support for OS threads at this time
• base MMU is just real memory but support for virtual memory should be added real soon, especially using TLB
• programs will be divided into two regions text and data (including both types of data and stack)
• at a minimum the file system should support the RCOS CP/M like file system, but preferably a more complete system that supports directory hierarchies should be included
• have a system call that allows a thread/process to give up CPU (useful in testing concurrency problems)
• simple mechanism for the addition of more system calls, probably to hard to do will always require re-compilation of compiler and Java

Class Clusters