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Initially
data was stored, not on magnetic devices but on either paper tape
or punched card. These devices would have patterns of holes depicting
a 0 and blanks depicting a 1. They were fed into a computer card
reader that recognised the code and the computer would act on
the instructions given. Damage to the tape or card was easy and
data recovery unreliable.
Things
moved on and later computers contained a core store memory. This
was a box full of magnetic ferrous rings, which had wires passing
through them. Basically when a ring was magnetised it became a
1. These devices were known as non-volatile memory because you
could remove the power and the storage status of the rings remained.
They were extremely expensive but became the basis of today’s
memory devices. Alternatively there is volatile memory that, as
expected, loses any memory when the power is removed. This type
of device uses semi conductor technology. A computers RAM is an
example of this device. We’ve all been there, not regularly
saved our data and lost it when the power went off.
So
last month we thought we would look at the various portable memory
devices around and some that have been superseded over the years.
Portability became an essential requirement, so new smaller magnetic
devices were developed. First on the scene was magnetic tape –
similar to that used in the old reel to reel tape recorders. Information
was stored serially and hence retrieval times were lengthy. Further
developments saw the floppy disc appear. The originals were 8"
and as their name incurs, were very flexible. It was basically
a flimsy disc coated with ferrous oxide that could be magnetised
accordingly. These were found mainly on industrial computers and
the early home computer enthusiast made do with magnetic cassettes
– just the same as the music cassette. These were infuriatingly
slow to load data and notoriously unreliable. 10 mins to load
Space Invaders, only for the loading to fail at the last knockings
was an all to regular occurrence. Patience was indeed a virtue!!!!!!!
Most
of you will remember the later floppy disc versions that were
reduced to 5¼ ". Originally they were singled sided,
had a read/write notch in the left hand top corner and held 360
Kbyte of memory. We soon found, however, if you turned them over
and put a notch in the opposite corner you got a double-sided
disc holding 720 Kbytes. It didn’t always work but gave
a high percentage success rate. Again they were a bit flimsy and
could easily be damaged making data irretrievable.
Along
came the 3½" floppy encased in a plastic body and
much more robust. They came in single density (360 Kbyte), double
density (720 Kbyte) and finally high density (1.44 Mbyte). Most
computers today have a floppy disc drive that will read any of
the above discs. Apple have dispensed with the floppy drive on
their later machines. It appears the floppy disc days are numbered
– even magazines put CD on their covers now.
An
extension of the floppy disc was the Iomega Zip Disc. Similar
in size to the floppy but chunkier, it could hold a massive 100
Mbyte of data. You did need a special Zip drive to read them but
their portability and the amount of storage made them extremely
popular. I still use mine. Later models included a 250 Mbyte version
and the Jazz disc, which held a whopping 2 Gbyte of data (but
at a price).
From
the humble floppy we have moved on to the CD that up to 700 Mbyte
of memory and latterly the DVD holding a massive 4.7 Gbyte. Developments
are in hand with duel layers and double sided versions offering
9.4 Gbyte. Data retrieval is fast and reliability extremely good.
Digital
cameras have driven a whole new range of storage device. One can
choose from Compact Flash, Microdrive, Smart Media, Sony Memory
stick, Secure Digital (SD) and the latest miniature cameras hold
small XD memory cards. Each device is a small card that fits inside
the camera and will record your pictures. Again they come in numerous
sizes from 16 Mbyte through to 4Gbyte and at prices to suit.
This
new range of memory has spawned a whole new range of peripherals
to read them. You do not have to read them into your computer
anymore. There are printers that will read the memory direct and
allow you to choose which picture you require. Now the High Street
offers you the chance to pop into shops like Jessops or Boots,
plug in your memory card and have your photos printed off professionally.
The need for computers and their peripherals aren’t even
necessary anymore.
Dave
Robb
A critical weakness found in many Microsoft programs looks like
it is about to be exploited by virus writers. The bug only came
to light last week, but code is now circulating that could be
used to attack vulnerable machines. Some security experts said
conditions were right to turn the bug into a widely exploited
problem. But others said there was still time to patch machines
and ensure that virus writers were prevented from scoring a big
success. Microsoft issued a critical security alert last week
telling users that there were problems with the way Jpeg images
are handled by Windows and many other programs it makes.
VULNERABLE
PROGRAMS
Windows
XP
Windows XP Service Pack 1
Windows Server 2003
Internet Explorer 6 SP1
Office XP SP3
Office 2003
Digital Image Pro 7.0
Digital Image Pro 9
Digital Image Suite 9
Greetings 2002
Picture It! 2002
Picture It! 7.0
Picture It! 9
Producer for PowerPoint
Project 2002 SP1
Project 2003
Visio 2002 SP2
Visio 2003
Visual Studio .NET 2002
Visual Studio .NET 2003
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