Term
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Definition
| Heap is memory set aside for dynamic allocation. Memory (variables) in heap must be destroyed. In Java the garbage collector does this.It's a bit slower than the stack. Memory leaks occur in the heap. |
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Term
| Primary purpose of the stack |
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Definition
| 1) Stores return address. When a subroutine is called, the address of the last instruction is pushed to the stack so the execution can continue once the subroutine is finished. 2) Local data storage. Memory space for local variables. 3) Parameter passing. Before a subroutine is called, parameters are pushed to the stack, 4) Arithmetic evaluation. Data is placed into registers usually to be operated on. Sometimes you need to have more data than there are registers, thus data will need to pushed onto the stack. |
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Term
| Stack pointer vs. a Frame pointer |
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Definition
| Stack pointer register indicates the top of the stack. The Frame pointer is a seperate register that addresses the stack relative to the frame relevant to the subroutine. Thus rather than SP+256+2 for the second memory spot in the frame, can use FP+2. |
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Term
| What does the CPU consist of? |
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Definition
| Datapth and control unit. |
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Term
| What is the control unit (CU) |
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Definition
| Logic which controls the datapaths. Determines how to process. Also regulates interaction between data path and main memory. |
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Term
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Definition
| ALU, multipliers, functional units that perform data processing. Provides routers for data to travel between functional units. |
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Term
| What does the datapath consist of? |
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Definition
| Intruction Register, Program COunter, Registers, Memory address register, memory data register |
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Term
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Definition
| Stores current instruction being executed. |
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Term
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Definition
| Stores address of next instruction. |
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Term
| General Purpose registers |
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Definition
| Located in dapath block, used by programs to store info. Reserved registers include stack pointer, frame pointer. |
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Term
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Definition
| Datapath block, Stores memory address from which data will be fetched to CPU, or address to which data is to be stored. |
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Term
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Definition
| Register of computers CU that contains data to be stored to RAM, or data to be fetched from RAM. |
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Term
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Definition
| Transfers data between components inside a computer. |
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Term
| What is the cache hit-rate? |
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Definition
| Proportion of accesses that result in cache hit. Measures effectiveness of cache. Better hit rate is good because misses delay execution, require data be transferred from memory (RAM). |
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Term
| Name some cache replacement policies |
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Definition
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Term
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Definition
| Write miss has no penalty, read misses do because data must be read from the RAM. Processor can continue execution while data is being written. |
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Term
| Cache replacement policies |
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Definition
| Determines what data is overwritten in the cache. Tries to predict which data is least likely to be used in the future. |
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Term
| Least Recently Used (LRU) Cache Replacement Policy |
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Definition
| Replaces the least used data. |
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Term
| Most Recently Used (MRU) Cache Replacement Policy |
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Definition
| Gets rid of most recently used item first. Assumes older an item is, more likely it is to be accessed. |
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Term
| Most Recently Used (RR) Cache Replacement Policy |
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Definition
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Term
| Segmented LRU (SLRU) Cache Replacement Policy |
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Definition
| : An SLRU cache is divided into two segments. a probationary segment and a protected segment. Lines in each segment are ordered from the most to the least recently accessed. Data from misses is added to the cache at the most recently accessed end of the probationary segment. Hits are removed from wherever they currently reside and added to the most recently accessed end of the protected segment. Lines in the protected segment have thus been accessed at least twice. |
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Term
| Least Frequently Used (LFU) |
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Definition
| Least used item is deleted. |
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Term
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Definition
| Every write to the cache causes a write to main memory. |
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Term
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Definition
| Writes not immediately mirrored to main memory. Cache tracks dirty locations (stuff written over in cache) If something is to be written over in the cache, it is written back to the main memory (RAM). |
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Term
| Problem with write-back policy |
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Definition
| In reading cache, a miss requires two memory accesses. Must first write dirty data to memory, re-read the new location back from memory into the cache. |
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Term
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Definition
| Can write data anywhere to the cache from anywhere in memory. |
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Term
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Definition
| Each entry in main memory has just one corresponding location in cache. |
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Term
| Benefits/Detriments of fully associative cache |
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Definition
| Is fully associative, then when accessing the cache you have the whole cache to check as the data could be stored anywhere as oppossed to a direct mapped cache where you know the data will be stored. But they suffer fewer misses as the data is able to be stored anywhere. CPU wastes less time reading from main memory. |
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Term
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Definition
| failed attempt to read or write a peice of data in the cace resulting in access to main memory. |
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Term
| Cache read-miss from instruction |
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Definition
| Most delay, CPU has to wait until instruction fetched from main memory. |
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Term
| Cacche read-miss from data |
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Definition
| Less than read-miss from instruction. CPU can continue while data is retrived because it has instruction. Can process something else while it waits. |
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Term
| Cache size and direct/associative caching |
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Definition
| Large cache is bettwe with direct mapped, while smaller is bettwe with associative. |
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Term
| Floating point unit (FPU) |
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Definition
| Part of computer system designed to carry out floating point operations. |
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Term
| How are numbers represented in 32/64 bit? |
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Definition
| First bit is sign of number, next 8 represents the exponent, the rest is the unsigned int. |
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Term
| Big endian versus Little endian? |
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Definition
| How are bytes are ordered. Determines where the most significant bit is - at the beginning or end? Matters especially when reading binary data transferred over a computer network. Need to make sure computers endienness is the same or convert. Basically, does the computer write data from left to right, or right to left? |
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Term
| English words ending in -ty |
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Definition
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Term
| English words ending in -ous |
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Definition
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Term
| English words ending in -ist |
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Definition
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Term
| English words ending in -ic |
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Definition
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Term
| English words ending in -end |
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Definition
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Term
| English words ending in -ant |
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Definition
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Term
| English words ending in -tor |
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Definition
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Term
| English words ending in -tion |
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Definition
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Term
| English words ending in -cal |
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Definition
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Term
| English words ending in -ment |
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Definition
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Term
| English words ending in -em |
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Definition
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Term
| English words ending in -ce |
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Definition
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Term
| English words ending in -cy |
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Definition
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Term
| English words ending in -ry |
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Definition
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Term
| English words ending in -em |
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Definition
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Term
| English words ending in -am |
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Definition
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Term
| English words ending in -cy |
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Definition
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