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⟦bb5de9c60⟧ Wang Wps File
Length: 1240 (0x4d8)
Types: Wang Wps File
Notes: Spelunked
Names: »~ORPHAN25.03«
Derivation
└─⟦0cd3644ba⟧ Bits:30006012 8" Wang WCS floppy, CR 0051A
└─ ⟦this⟧ »~ORPHAN25.03«
WangText
D̲I̲S̲C̲ ̲C̲O̲N̲T̲R̲O̲L̲L̲E̲R̲ ̲R̲A̲M̲ ̲A̲C̲C̲E̲S̲S̲ ̲M̲A̲N̲A̲G̲E̲M̲E̲N̲T̲ ̲
The controller cannot manage the receipt of instructions
and data from transmission of data to the I/O Channel
together with the receip of data from or transmission
of data to the disc. Since the time t…0f…CONTR…0e… is of the
same order as the transfer time on the I/O Channel
(refer section 4.4) we may, however, assume this constraint
to be negligible.
D̲i̲s̲c̲ ̲S̲e̲e̲k̲ ̲T̲i̲m̲e̲
For calculationof seek time it is assumed that the
d̲a̲t̲a̲ are uniformly distributed, i.e. the probability
of the data being located on a certain track is the
probability of the head having to move from that track
to any other track and equal to 1/N where N is the
nmber of tracks per head.
From J. Martin, Design of Real Time Computer System,
Chapter 28, page 441 the mean number of tracks to be
traversed and the variance are found as
X = (N…0e…2…0f… - 1)/3N N/3
6…0f…x…0e……0e…2…0f… = (N…0e…4…0f… + N…0e…2…0f… - 2) / 18N…0e…2…0f… N…0e…2…0f…/18
Fig. 4.5.1-2 presents the SEEK TIME as a function of tracks
moved and the CAMPS linear approximation to the seek time: I̲t̲
̲i̲s̲ ̲i̲m̲p̲o̲r̲t̲a̲n̲t̲ ̲t̲o̲ ̲n̲o̲t̲i̲c̲e̲ ̲t̲h̲a̲t̲ ̲t̲h̲e̲ ̲C̲A̲M̲P̲S̲ ̲d̲a̲t̲a̲ ̲m̲a̲y̲ ̲b̲e̲ ̲c̲o̲n̲s̲t̲r̲a̲i̲n̲e̲d̲
̲t̲o̲ ̲t̲h̲e̲ ̲f̲i̲r̲s̲t̲ ̲2̲0̲0̲ ̲t̲r̲a̲c̲k̲s̲ ̲p̲e̲r̲ ̲h̲e̲a̲d̲:̲ the 5 heads will provide one
a
