CS433g Computer System Organization - Fall 2005 Practice Set Solution for Chapter 7 - Prof, Assignments of Computer Architecture and Organization

Download CS433g Computer System Organization - Fall 2005 Practice Set Solution for Chapter 7 - Prof and more Assignments Computer Architecture and Organization in PDF only on Docsity! CS433g: Computer System Organization – Fall 2005 Practice Set (Chapter 7) – Solution Due Date: None Question 1 The I/O bus and a memory system of a computer are capable of sustaining 1000MB/sec without interfering with the performance of an 800-MIPS CPU (costing $50,000). Here are the assumptions about the database software that must run on this computer: • Each transaction requires 2 disk reads plus 2 disk writes • The operating system uses 15,000 instructions for each disk read or write • The database software executes 40,000 instructions to process a transaction • The transfer size is 1000 bytes per disk I/O You have a choice of two types of disk organizations: • Several small disks that store 500MB each and cost $100 each • Several big disks that store 1250MB each and cost $250 each Either disk system can support on average 30 disk reads or writes per second. You may approximate 1 MB as 1,000,000 bytes and 1 GB as 1000 MB. The system must support 10 gigabytes of data in the system. Assume that disk requests can be spread evenly to all the disks, in a round robin fashion (i.e., I/O request 1 goes to disk 1, request 2 goes to disk 2, etc.). Part A What is the maximum transactions per second (TPS) rate possible with each disk organization? For this question, you should compute the peak TPS that would be allowed by each system component (CPU, bus, disk) and then determine the TPS from the limiting component. Solution: We need 10GB of disk space so this requires either 20 small disks or 8 large disks. Each transaction requires (2 reads + 2 writes) * 15,000 + 40,000 = 100,000 instructions per transaction. Unit Performance # of Units Demand/Transaction TPS Limit CPU 800 MIPS 1 1 MIPS 8,000 Bus 1000 MB/s 1 1000 Bytes 250,000 Small Disk 30 I/Os per second 20 4 I/Os 150 Large Disk 30 I/Os per second 8 4 I/Os 60