Computer Organization
Q112.
Consider a disk drive with the following specifications: 16 surfaces, 512 tracks/surface, 512 sectors/track, 1 KB/sector, rotation speed 3000 rpm. The disk is operated in cycle stealing mode whereby whenever one 4 byte word is ready it is sent to memory; similarly, for writing, the disk interface reads a 4 byte word from the memory in each DMA cycle. Memory cycle time is 40 nsec. The maximum percentage of time that the CPU gets blocked during DMA operation is:Q113.
What is the bit rate of a video terminal unit with 80 characters/line, 8 bits/character and horizontal sweep time of 100 \mu s (including 20 \mu s of retrace time)?Q114.
For the daisy chain scheme of connecting I/O devices, which of the following statements is true?Q115.
An interrupt in which the external device supplies its address as well as the interrupt requests is known asQ118.
RST 7.5 interrupt in 8085 microprocessor executes the interrupt service routing from interrupt vector locationQ119.
Consider the following statements. I. Daisy chaining is used to assign priorities in attending interrupts. II. When a device raises a vectored interrupt, the CPU does polling to identify the source of interrupt. III. In polling,the CPU periodically checks the status bits to know if any device needs its attention. IV. During DMA, both the CPU and DMA controller can be bus masters at the same time. Which of the above statements is/are TRUE?Q120.
Choose the correct alternatives (more than one may be correct) and write the corresponding letters only: The TRAP interrupts mechanism of the 8085 microprocessor: