What to do. Implement the Devices module of OSP2.
The project files are found on Blackboard in the Assignments section.
Details of what you are supposed to do are provided in the OSP2 documentation (the chapter
on device management). It is required that you implement the following scheduling strategy:
• Initially there is one queue of I/O requests.
• When the device starts processing the first request in that queue, the queue is closed and
any subsequent I/O requests are added to another queue.
• When the device is done with the first queue, it switches to the second. That second queue
is then closed and new requests go into a third queue, etc.
Note: This does not mean your implementation should use an unbounded number of
queues. The above is a description of the desired behavior, not an implementation guideline.
• Within each queue, requests are processed using SSTF (shortest seek time first).
Your objective in this project is to get your implementation to run under OSP2 without errors
and warnings with the parameter files that appear in the Misc subdirectory (the files with the
.osp extension). As explained previously, occasional errors (every 5-10th run) should not be a
cause for concern due to some synchronization issues in OSP2.
Statistics. Compare and explain your statistics with respect to those produced by Demo.jar
(Demo.jar uses the FIFO algorithm). The statistics of interest are:
• Total number of tracks swept on each device.
• Average number of tracks swept per I/O request.
• Average turnaround time for I/O requests.
• System throughput.
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These statistics are part of the snapshots in the file OSP.log, which is produced when OSP2 runs.
The meaning of these statistics is explained both in the textbook and in the OSP2 manual.
