I need help with question number 2. Problem Statement: The predominant storage i
ID: 3552319 • Letter: I
Question
I need help with question number 2.
Problem Statement:
The predominant storage inside a computer systems are on disks drives. SCSI disks are
the standard disks in most Unix Workstations from Sun, HP, SGI, and other vendors.
They are also the standard disks in Macintoshes and Higher-end Intel PC's, especially
network servers. Consider the Wide Ultra4 SCSI which transfers data packets in 16-bit
bursts at 160 MHz with a maximum throughput of 320 MB/sec. The data transfers at
higher rates can result in random-noise pulse changes from a 0 to 1 and 1 to a 0. As the
speed of processors and electronic communications increases, these parity flips become
more prevalent and the inability to detect when these errors occur can be fatal. As a
Design Engineer you have been requested to create system for the transmission of these
8-bit packets from an I/O Controller to Memory using Error Correcting Code over 12-bit
data bus line. Wide SCSI contains a 68bit bus; however for the sake of simplification we
are only concerned with the data bits. The other bits in the SCSI bus are for bus
arbitration, synchronization, power management, etc. In this project, we will use even
parity.
2) Construct a 12-bit Data Transmission bus to send the binary data and parity bits over to Memory.
Explanation / Answer
To calculate parity bits for 8 bit data,
P1: = XOR of bits(3,5,7,9,11)
P2: = XOR of bits(3,6,7,10,11)
P3: = XOR of bits(5,6,7,12)
p4: = XOR of bits(9,10,11,12)
** p1-p4 parity bits, and bits/parity bits numbered 1-12 from left to right) **
so it is, P1,P2,bit3,P3,bit5,bit6,bit7,P4,bit9,bit10,bit11,bit12
as you have given in the figure. NOw just connect this 12 bits to input of memory to obtain the data bus