ZX-News #39 18 августа 1997

Железо

Winchester - What is the "Winchester" and what it is.

        Winchester ON SCORPION'E

                  FOR

               Dummies



                         (C) Yuri Buravtsov


         What is - "Winchester"

           and for what it is


  These devices are similar to the one on themselves
computers, which they are installed.
People do not understand how they need them
until then, until the start to use them. Suddenly it turns out 
that these devices are of vital necessity, and this the need is 
growing every day of their operation. After the hard disk drive 
Everyone is wondering how it can do without him. It helps to 
improve performance daily work on loading

certain programs. Because
it allows you to organize the information very quickly, greatly 
increasing system performance, it seems that

other components of the computer uludshayut
their characteristics.


  I, as a member of the editorial board, to work with
vast amounts of information winchester
was simply vital. Prior to its use, I messed around with floppy 
disks, as once upon a time - from audio cassettes,

where he kept a variety of programs for the ZX
Spectrum ... Do you remember that time? What
feeling you have when this occurs?


  What is - a hard drive? Consider
it in more detail.


  Unlike a floppy disk drive,
read / write heads do not touch the hard drive with the disc 
surface. The reason is that the hard drive is constantly 
spinning at speeds from 3600 rpm and above, which results in 
high speed information exchange. But still, head is at within a 
few microns from the working the disk surface. Therefore, the 
space in exchange zone should be mechanically clean. What does 
this mean? Any speck of dust on compared with the distance 
between the head and surface seems to boulder, which is able to 
change the direction of the head. And this, in turn, can lead 
to so-called fall of the head. The magnetic coating disk gets 
deep furrow. Estesstvenno, at this place already

exchange of information with a computer is impossible.


  Therefore, all hard drives hermetically
covered with metal casing and the inner disk space is filled 
with inert gas. 


  I mentioned the concept of "working surface". What does this 
mean? 


  The fact is that modern hard drives are equipped, as a rule, 
several disks (pancakes), one above others. They all revolve on 
the same axis same rate. Multiple disks substantially increase 
the capacity of a hard drive (this is clear by definition). 


  When the hard drive does not work, then head
read / write pressed to the surfaces, and
rotating disc creates an air stream, which as it lifts the head.
Therefore, at the start or stop the hard drive may damage the 
magnetic layer disc. Older models of hard drives before 
shutting down the power needed to run a special program which 
has been given head on the unused space

disk, this process is called parking
heads. In modern hard drives is
automatically. In addition, when
hit, or any other casual handling with the hard disk can occur 
shift heads with unused surfaces to the used. Therefore, 
current models of hard drives have a locking mechanism that 
keeps the head in a parking zone for a while off.



  In general, the modern technology of magnetic hard disk 
coatings can not fear accidental falls heads

as now cover so strong,
that the head just bounces off the disc
almost fell on him. In the worst case knock out only one sector 
... 


  The closer the head is a disk
so it reads more reliable information, so in this way is also 
achieved increase the density of the read / write.



  There are several types of interfaces
drives. The most common
are two: IDE (Integration Drive
Electronic) and SCSI (Small Computer System
Interface). The SCSI interface allows you to work faster with 
arrays of data than the IDE, therefore it is more expensive. At 
the same time there is a kind of IDE - Enchanced

IDE - integrated advanced
control electronics drives, allowing
use drives over 500 MB (IDE interface does not allow it). At 
this moment of E-IDE interface is the most

common.


  When buying a hard drive is, so to say, "look to the future 
... What is mean? This means that the best thing to buy a 
reliable and large enough capacity. After all, Winchester is 
useful in the future not only for Spectrum'e, but also on other 
machines ... In addition, the memory, as indeed, money is never 
too much. I have a hard drive capacity 1.08 GB (gigabytes) of 
which is already in use exactly one-third ...



  By the way, a couple of words about the capacity of the disc. 
RAM device manufacturers believe that a kilobyte 1024 bytes, 
but megabyte - 1024 kilobytes. It is this "Binary" megabytes, 
and we believe in this MB. On the other hand, hard drive 
manufacturers believe that MB - it is a million bytes. 
Therefore sets a standard IDE limit at 528 MByte system 
manufacturers hard disks is equal to 504 "real" megabytes. Not 
so if hard drives look more than they really are?



  So beware.


  About models. Most be acceptable from the point
of performance - it is Western
Digital and Seagate, compactness - Seagate,
value - Conner ... In general, prices
Hard drives are constantly falling, because developed more and 
more hard drives with more capacity. Three or four years ago

sensation were hard drive capacity 540 MB,
now number 9.1 GB of very few people will be surprised ...