Work Sheet 1

Consider a memory system with the following parameters:
T_cache = 100 nanosec C_cache = 0.01 cents/bit
T_memory = 1200 nanosec C_memory = 0.001 cents/bit
Hit Ratio = 0.95
a) What is the cost of 1 MB of main memory?
b) What is the cost of 1 MB of main memory using cache technology?
c) Design a main memory/cache system with 1 MB of main memory whose effective access time is no more than 10% greater than cache memory access time. What is its cost?

A main memory system consists of a number of memory modules attached to the system bus. When a write request is made, the bus is occupied for 100 nanosec by the dat, address and control signals. During the same 100nanosec and for 500nanosec thereafter memory module executes one cycle accepting, and storing the data. The operation of the memory modules may overlap, but only one request can be on the bus any time.
Assume that there are eight such modules connected to the bus. What is the maximum possible rate (in bytes per second) at which data can be stored.