24 Questions
What is the primary purpose of introducing a cache in a computer system?
To balance fast and cheap memory
What is the key challenge in storing data in the cache memory?
Determining the most frequently accessed data
What is the benefit of using a cache in a computer system?
It makes the common case faster
What is the main difference between static RAM and dynamic RAM?
Static RAM is faster than dynamic RAM
What is the primary benefit of the principle of locality?
It makes the cache more efficient
What is the main advantage of using cache memory?
It keeps a copy of the most frequently used data
What is the relationship between the cache and main memory?
The cache keeps a copy of the most frequently used data from the main memory
What is the general trend in the cost of memory as the size increases?
The cost of memory decreases as the size increases
How many blocks does a direct-mapped cache hold with a 4-bit index?
16 blocks
What is the size of the tag in the cache with a 16-bit address and a 4-bit index?
12 bits
Why are one-byte cache blocks not efficient?
They don't take advantage of spatial locality
What is the total number of bits required to build the cache with 16 blocks, each with a 12-bit tag, 1 valid bit, and 8 data bits?
336 bits
How can we take advantage of spatial locality in a cache?
By increasing the block size
What determines where a byte of data belongs in a cache with 2k blocks, each containing 2n bytes?
The main memory address
What is the purpose of the valid bit in a cache block?
To indicate the block is valid
Why do we use a larger block size in a cache?
To take advantage of spatial locality
What is the purpose of the cache index in a direct-mapped cache?
To select the correct block to access
How many blocks does the cache hold in a byte-addressable machine with 16-bit addresses and a cache with a 4-bit cache index?
16
What happens when the cache is full and a new block needs to be loaded?
The least recently used block is replaced
What is the size of each block in the cache described in the content?
1 byte
How many bits of storage are required to build the cache?
The answer depends on the cache size
What is the main advantage of using a direct-mapped cache?
It is simpler to implement
What is the purpose of the tag in a cache block?
To identify the memory address
What happens when a cache miss occurs?
A new block is loaded into the cache
Study Notes
Types of Memory
- Static RAM: 1-10 cycles, $5, 128KB-512MB
- Dynamic RAM: 100-200 cycles, $0.10, 128MB-64GB
- Hard disks: 10,000,000 cycles, $0.0005, 20GB-8TB
Cache Memory
- Introduces a balance between fast and cheap memory
- A small amount of fast, expensive memory that keeps a copy of the most frequently used data from the main memory
- Increases overall memory access speed, as most frequently accessed data is serviced by the cache
- Less frequently used data is accessed from the slower main memory
The Principle of Locality
- Difficult to determine what data will be most frequently accessed before a program runs
- Hard to know what to store in the small cache memory
- Addresses are usually 32 bits, with 22 bits for the tag and 10 bits for the index
Cache Replacement Policy
- If the cache fills up, a new block is loaded into the cache, automatically overwriting previously stored data
- This is a least recently used replacement policy, which assumes older data is less likely to be requested than newer data
Cache Organization
- A byte-addressable machine with 16-bit addresses and a cache with 4-bit index
- The cache holds 16 blocks, each holding one byte
- 336 bits are required to build the cache
Spatial Locality
- One-byte cache blocks don't take advantage of spatial locality, which predicts that an access to one address will be followed by an access to a nearby address
- Increasing the size of the block can help, by copying n bytes from main memory and placing it in the cache
- This block is stored in the cache along with the tag bits and valid bit
This quiz compares the characteristics of different types of computer memory, including Static RAM, Dynamic RAM, and Hard Disks. It covers their access times, cost, and storage capacities.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
