We will start by configuring a system to complete a sort in the least possible time, with no limits on how much we can spend. To get peak bandwidth from the sort, we have to make sure all the paths through the system have sufficient bandwidth.
Assume for simplicity that the time to perform the in-memory sort of keys is linearly proportional to the CPU rate and memory bandwidth of the given machine (e.g., sorting 1 MB of records on a machine with 1 MB/sec of memory bandwidth and a 1 MIPS processor will take 1 second). Assume further that you have carefully written the I/O phases of the sort so as to achieve sequential bandwidth. And of course realize that if you don't have enough memory to hold all of the data at once that sort will take two passes.
One problem you may encounter in performing I/O is that systems often perform extra memory copies; for example, when the read() system call is invoked, data may first be read from disk into a system buffer, and then subsequently copied into the specified user buffer. Hence, memory bandwidth during I/O can be an issue.
Finally, for simplicity, assume that there is no overlap of reading, sorting, or writing. That is, when you are reading data from disk, that is all you are doing; when sorting, you are just using the CPU and memory bandwidth; when writing, you are just writing data to disk.
Your job in this task is to configure a system to extract peak performance when sorting 1 GB of data (i.e., roughly 10 million 100-byte records). Use the following table to make choices about which machine, memory, I/O interconnect, and disks to buy.

Assume you are buying a single-processor system, and that you can have up to two I/O interconnects. However, the amount of memory and number of disks is up to you (assume there is no limit on disks per I/O interconnect).
a. What is the total cost of your machine? (Break this down by part, including the cost of the CPU, amount of memory, number of disks, and I/O bus.)
b. How much time does it take to complete the sort of 1 GB worth of records? (Break this down into time spent doing reads from disk, writes to disk, and time spent sorting.)

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CPU Slow Standard 2 GIPS Fast Memory Slow StandardGB/sec Fast l/O interconnect Slow Standard 160 MB/sec $100 Fast Disks $200 $1000 $2000 1 GIPS 80 MB/sec $50 4 GIPS 320 MB/sec 400 $70 $120 $300 512 MB/sec S100/GB Slow 30 MB/sec 5200/GB Stdard 60 MB/sec S500/GB Fast 2 GB/sec 110 MB/sec