Memory for disk arrays
Floppy disk controllers with RAID can hardly be recommended as a RAID Controller
for even mid-level server (no cache, is not supported RAID-3 or -5). At the same
time, this is an excellent choice for entry-level servers, graphics terminals
and systems that nonlinear video installation, for which the main parameter is
the ratio tse-na/proizvoditelnost. ii. RAID controllers working together with
the existing disk controller context. These RAID controllers are designed to
work with system Boards, which hav integrated disk controller. Thus, the
controller on the board is only "logical" part RAID controller, and data
exchange with the functions assigned to the floppy drive disk con-troller,
integrated on the motherboard. Such "truncated" controllers are usually
supported by many full-function RAID controller, and at the same time, are on-lot
cheaper. However, the decision is not without shortcomings. The most important
of them - each "truncated by the" controller rigidly "tied" to a particular type
of disk controller chips and, consequently, will work only on those motherboards,
which is integrated in such a chip. Combining controller with RAID disk
controller via PCI much tyre-gruzhaet at last, pulling other I / O operations.
To improve the overall productivity of the system on some motherboards put
additional interface, called PCI-RAIDport and allowing RAID controller directly
exchange data with integrated on the motherboard, SCSI controller. RAID
controllers working together with the existing disk controller, are not cost
much more than the value of quality Ultra2 SCSI disk controllers, and at the
same time, the characteristics of a fully functioning concede little-RAID
controllers (absence of shows battery module for the protection of cache and is
not clustering provides RAID controller). The disadvantage may be considered
that these controllers "sharpened" to work with certain types of motherboards-ing,
which reduces the area of their application.
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