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Transferring Data – Primary Memory to Secondary Storage. AS Computing. This exact question has come up in 2 previous past papers, and can be worth 6+ marks. “Describe the use of interrupts and buffers when data is transferred from primary memory to a storage device.”. Define Terms.
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Transferring Data – Primary Memory to Secondary Storage AS Computing
This exact question has come up in 2 previous past papers, and can be worth 6+ marks. • “Describe the use of interrupts and buffers when data is transferred from primary memory to a storage device.”
Define Terms • Primary Memory – RAM, IAS • Secondary Storage – USB Memory Stick • Both transfer data at different speeds • Therefore need to use • Buffer • Area of temporary memory used to transfer data between 2 devices • Interrupt • Method of stopping the CPU so it can perform a task and return to the previous task.
Key Points • Data sent to buffer from primary memory. • This allows processor can continue with other tasks • Interrupt sent when buffer is full. • Buffer is emptied to storage device. • Buffer used to allow RAM and secondary storage device to transfer data as they do so at different speeds. • When buffer is empty • Interrupt is sent to processor • To request buffer refill • Process cycles until all data is transferred
Additional Points • Error checking takes place once data is transferred. • Interrupt given priority to CPU when buffer is full, required refilling • Plan your answer. Use clear English. Read it first before writing on question paper. EXAM Technique!