IGNOU BCA 1st sem Solved Assignment -Differentiate between the following: (i) Random Access vs. Serial Access (ii) Parallel port vs. Serial port

Differentiate between the following:

(i)     Random Access vs. Serial Access

(ii)   Parallel port vs. Serial port

Ans

The main difference between random access and serial access, IN GENERAL, is that with random access you have roughly equal time to any given address. This is true of RAM, of SSDs,etc. With a hard disk, you almost get that—within the swing of the head. So reading data serially off a hard disk is faster than randomly.

With a tape drive, you have to actually seek to where the data is—that’s what’s going on on the old-school mainframes when you see tapes spinning fast, then slowly. Reading contiguous data is significantly faster than reading random data.

Comparing random versus sequential operations is one way of assessing application efficiency in terms of disk use. Accessing data sequentially is much faster than accessing it randomly because of the way in which the disk hardware works. The seek operation, which occurs when the disk head positions itself at the right disk cylinder to access data requested, takes more time than any other part of the I/O process. Because reading randomly involves a higher number of seek operations than does sequential reading, random reads deliver a lower rate of throughput. The same is true for random writing.

You might find it useful to examine your workload to determine whether it accesses data randomly or sequentially. If you find disk access is predominantly random, you might want to pay particular attention to the activities being done and monitor for the emergence of a bottleneck.

differences between Serial port and Parallel port

Subject	Serial Port	Parallel Port
Pins	9 pins	25 pins
Type of port	Male port	Female Port
Color	usually Purple in color	Usually Green in color
Data Transfer Rate	Slower than Parallel Port	Faster than Serial Port
Moving Bits	Serial move bits inline, one at a time.	Parallel moves bits next to each other
Usage of Wire	Serial ports are only used 2 wires for transmitting and receiving data	Parallel Port used 8 or more wire for transmitting and receiving data.
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