Project ForgeComputer Organization & Architecture
Memory Hierarchy & Floating Point
GATE 2016
Hard
The size of the data count register of a DMA controller is 16 bits. The processor needs to transfer a file of 29,154 kilobytes from disk to main memory. The memory is byte addressable. The minimum number of times the DMA controller needs to get control of the system bus from the processor to transfer the file is ____.
456
Explanation
A 16-bit count register can transfer at most 2¹⁶ = 65536 bytes per bus-control session. File size = 29154 KB = 29154×1024 bytes = 29,853,696 bytes. Number of sessions = ⌈29,853,696 / 65536⌉ = ⌈455.5625⌉ = 456.
Source: GATE CS 2016 (Session 1 / Set A) (2016)
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