With the advent of modern small and, generally speaking, fairly reliable
hard drive for the masses "irregular" means users reserve
Copy as it overshadowed the second plan. Of course, it is understandable that when
there is a local network, regular backup of information simply needed. And
Still, you can specify at least seven good reasons why, and
"Informal" you abandon the purchase of equipment
Backup simply unreasonable. Comment on the reasons.
We know many cases where, instead of to format a floppy disk,
you start to format the hard drive and spohvatyvalsya only when
have already lost the most recent or the most valuable information. In this case,
imnno backup device could be a kind of
insurance policy.
Of course, modern vinchestery virtually no malfunctions. But many of the
at home users who have the opportunity to update their
"Material part" quite regularly? Well, "aging" hard drive, you want to
it or not, is gradually turning into a "bomb" in slow motion.
Perhaps no secret that the "screw" ordinary users tend to score almost
"Almost under the strap." But of all the stored information is used intensively,
only 30-40%, the rest is usually dead weight: and erase pity, and
rewrite nowhere. Is not difficult to guess that in this case, the availability of devices
Backup could significantly ease the life by allowing the release of
on the hard disk has enough space.
In the event of earthquakes, fires, theft and other obsoyatelstv have a copy of all
information from your hard drive (or hotyaby part of it) is not too bad.
Software, takes a few megabytes, it is now no
surprise. "Cool software" along with the various libraries, by the way, may take
significantly more space. Especially "prozholivymi" to the disc space
are, inter alia, various systems engineering (CAD / CAM), computer
schedule. In this case, for example with a contractor from another city (and
there is, of course, uobeih organizations compatible devices reserve
Copy, for example streamer), the transfer of large amounts of information
it seems very comfortable.
There is usually bypassed by "informal" user probemy
power supply. Typically, the acquisition of uninterrupted power supply (UPS)
prolonged, or because of lack of money, or because of a misunderstanding of the problem.
Maybe, in some cases, the purchase of backup devices
it will be easier to justify?
Well, another simple example. Everyone knows that difragmentatsiya files
vinchestere significantly slows access to the data recorded on it (on
some information in two or even three times). Of course, you can use
Special programs that allow rewriting available for files
consistently cluster for the cluster. But we should not forget that after
To restore information from the device backup mode
file-by-file, the problem is solved, but how would automatically.
So, the backup device is a device to contain
information as a reserve, protecting it from everyday occurrences.
I am in the abstract describe the types of backup devices: tape
Optical, magnitopticheskih drives, and others.
Streamer.
Streamer is called a device connected to a computer for recording and
playback of digital information on the tape with the tape. Main
Appointment-backup.
Now a difficult question: what streamer buy? Streamer for small
LANs, as well as "informal" user should be responsible
Standards QIC-40/80.
First, it ensures at least some compatibility. In addition, it is the quality of
this case is not only a single specification, but
predolagaet compatibility of the "bottom-up". Thus, katridzh
(cassette), recorded on tape Standard QIC-40, will
read utroystve performed by the standard QIC-80. In the voryh when
connecting to a computer tape otvechayuchih specifications QIC-40/80, as
rule, no special difficulties and problems. Such devices are not in vain
known as "floppy-tape" - the fact is that they can connect to the existing
in any "personalke" controller floppy disks. Benefits used
Technical solutions often obvious. Nevertheless, manufacturers
and a special controller, which can speed
data exchange. And third, each katridzhe before the devices can
maintained between 120 and 250 megabytes of information (if you use data compression)
that typically exceeds or an appropriate amount of available hard drive.
An important factor is that streamers that meet standards
QIC-40/80, produced a number of large firms, which in turn generate more
expands the range of compatible devices.
Horsham known in the world streamers Jumbo120 ($ 200) and Jumbo250 (from $ 280).
We must pay tribute to the details firm Colorado Memory Systems, have developed these
model, which held just a tremendous amount of work, detailed check
their new models streamer with computers different companies. It was studied more
400 different models of IBM-compatible computers.
Models streamer Jumbo 120 Jumbo and 250 meet specifications QIC-40 and QIC-80
respectively. The user is offered two options such
devices: the interior or exterior. In the latter case, embedded devices
"Dresses in elegant plasmassovy corpus, which, together with cables and other
enhancements included in the company's range of KE-10. Incidentally, the model can Jumbo 120
use two speed transmission - 250 and 120 Kb / s, as
known, coincides with the standard values for controllers, floppy disks
PCs type XT and AT. Jumbo streamers have software support for compression
data, the company's algorithm Standard QIC-122. According to the
Company Colorado Memoy Systems, the use of effectiveness of coding information
allows compress data on 6:1 to 1,3:1 with a mean of 2:1. In
algorithm is based on QIC-122 was based on the powerful compression algorithms Lemnelya-Zeeb;
who was among the first to effectively use the company Stac Electronic,
developed a special chip encoder-decoder data. Incidentally, the use of
a special controller TC-15 (TC-15M for PS / 2) instead of the standard for
floppy disks to increase performance (speed archiving
information) models streamer 120 Jumbo and Jumbo 250 c 2,2 to 4,4 and 8,8 MB / min
respectively. Since the compression algorithm in this case is implemented in hardware,
then its implementation should be virtually "zero" time. To control
transfer data using the cyclic redundant code (CRC), but
error correction (ESS) - Reed-Solomon algorithm.
Especially I would like to note the fact that controllers firms Colorado
Memory Systems does not require manual installation of switches and about sobodnyh
addresses, numbers interrupt IRQ channels and direct access DMA. The conflict between
hardware platform does not arise, since used in the installation
software uses a special algorithm testing, which is 95%
cases, he defines the parameters necessary for installation. In the remaining 5%
of the necessary installations made by "software"
switches, which are recorded on a computer screen.
Software supplied with models streamer Jumbo, fully
compatible with network packages such companies as Novell, IBM, 3COM. It should not be
Also remember that for the devices, corresponding specifications QIC-40/80,
may use common software, such as package RS-Tools
Company Central Point Software.
Jumbo-one of the most inexpensive and quick tape alleged to
the domestic market.
One promising direction is to use as a conventional streamer
VCR.
In the city of Zelenograd mastered serial production fees "Arvid-1020" opens
all users of IBM-compatible PC access to backup data on
video cassette. It does not cost much more expensive than other controllers for
Bus ISA, and provides an opportunity to connect to a PC and used as
Any drive recorder. Access to data on the tape is in
emulation subsection HD, while the user is working with friendly
Program-coated done in the style of Norton Commander.
Advantages ARVID:
a) a relatively high speed of the exchange;
b) the reliability of storage (advanced Hamming code);
c) high capacity, low cost carrier;
d) the possibility of using a VCR.
Together with the controller comes software that supports on the
tape multilevel hierarchical system. Elements of the data here may be
an arbitrary files and directories that users can copy,
rename, delete, merge and sort, ie, to perform all the same
thing that lets you do with files DOS. To find information in the file
System ispodzuetsya own index of the tape. His working copy is stored
on the disk, and backup - directly on the tape. There are automated
the procedure set for a specific video, context-dependent
Hints and detailed documentation.
The fee "ArVid-1020" cost-effective and easy to use, as evidenced
experience of its application for solving image processing, geophysics,
cartography, as well as a complete set of professional workstations. On
three-hour tape can be recorded (at a speed of 200 Kb / s) up to 2 GB
information, the storage will cost 600 times cheaper than on diskette
high density.
"Arvid-1020" is not predyavlyaet high quality and options straps
VCR. It works reliably import and domestic vehicles,
while ensuring full portability of data between computers.
This board uses 16-bit DMA, poetmu can not work with some
motherboard (which this feature is not implemented). One of her
shortcomings, very GREET. Prepared for serial production fees 1030 (without
Use DMA) and 1040 (with built its own 286-processor).
Finally, a few words on the recorder. "Arvid" work with "vidikom on
principle: the worse the better. We do not recommend expensive video recorders,
a correction signal Tri Logic. For the video "PANASONIC" a special
transition cord.
Over the past few years as an alternative to the drive nesemym
magitnyh hard disk (HD), or hard drive, there are drives with a replaceable
bearer. The notion of "drives with removable media brings together a wide variety of
products of optical disk drives and cartridges to swap HD, which
- can be learned from your computer and capture home in diplomacy. "
Normal Drive (NGMD) also enjoyed "removable media" - disks, but
because of their low capacity and small-time work to the bottom (about 3 months. mode
read-write for a floppy disk), this device to another oblast
Use: The main function - the transfer of programs from your computer to another
computer and, in the absence of alternatives for backup storage. Not
replaced with a market described below devices because of its price and the price of diskettes to
it ten times less.
All considered further device has one common feature, which
distinguishes them from the drive: they are removable media has a large
capacity (20 MB).
Such removable external memory subsystem, usually a little less
speed analogues nesmennogo type (hard drive) and more expensive, but
there are a number of important preimuschestv.Poskolku these drives are replaceable
and weigh no more than 0,5-1 kg, they could easily transpose. Moreover, thanks
removable media you can actually delete the unauthorized
access to confidential data - not leave them on the internal hard drive
computer where they can use or accidentally spoil.
All those memories, from the standpoint of the buyer shall have the unquestionable
dignity, as infinite capacity memory. Initial cost of the system
pokazzatsya can be quite high, but by the time you have to write to
It ssvoi first 2Gb, it has dropped to a typical figure for the Interior
Hard Disk Drives. If the desired amount of memory will increase to 4GB and
more, the cost per megabyte decline further.
Some sub-systems that use removable media have quite high
speed and could play a role in the computer's main or
Support your hard disk. Other sub-systems in this category are suitable for
Such additional applications, such as the organization backup memory is very large
tanks; long-term archival storage of information that is rarely used
again. There are also external memory subsystem, as the optical drives
Disk-type WORM ( "with a single entry and multiple readings), which
best suited for archiving data.
These devices are very raznyatsya from each other in technology, design, price
memory capacity and the area of alleged use.
Consider disk drives that use removable media, starting with a
the oldest drives - drives that use removable media type vinchesterskogo
Company SyQuest, then drive type Bernoulli (Bernoulli), optical
magnitooptichesie drives, flopticheskie drives, complete title
consideration of such a device for transferring and storing information, such as outdoor
portable hard drive. Lasers CD-ROM drive and the CDR will be considered in
a separate chapter.
Drives that use removable media vinchesterskogo type performed on the basis of replacement
vinchesterskoy subsystems company SyQuest, which is the world's first mastered
production vinchesterskih nakoiteley removable media for personal
computers. The idea in principle is quite simple - to shift the cassette is placed
only the hard disk. The engine and transmission control electronics
remain in the case. The design provides storage
special funds for building the flow of air and filters do not allow
Violations of efficiency nakopitlya because of the polluting particles.
Removable media vinchesterskogo type.
Removable media vinchesterskogo type - the first kind of replacement
media-based hard disk drives for personal computers - originally
suffered because of insufficient reliability. This is a very difficult engineering
task - to create a sealed unit with hard drive, which could be
move in "diplomacy" (thereby exposing to dust and other
adverse external factors), and then inserted into the drive and force
rotate at a speed of 3600 revolutions per minute and more. The company SyQuest
Technology has become a giant and became a de facto monopoly - it
controlled about 90% of the world market for hard disc with a replaceable
bearer.
The rapid development of technology and conventional removable hard drive helped
improving technology for magnetic materials, increased
integration of electronic devices, reducing the size of mechanical assemblies.
Napylyaemy thin-film media
In the mid 80-ies occurred on a massive shift from a non
oxide coating of magnetic material (which applied the method of irrigation) to
napylyaemy thin film that provides a smooth and resilient to external
influences the surface. This has enabled closer head read / write to
magnetic layer and increase storage density. In addition, when using
Technology spraying was possible over the magnetic layer to cause security
the carbon layer, the hardness of which commensurate with a hardness of diamond.
Improved lubricants.
Thin-film technology has created on the surface of the disc sliding
layer that prevents "zalipaniyu 'heads (who sometimes happens with old
Capacitors with oxide-coated). Even when you stop
drive heads descend to the surface, his theoretical term
Service is not decreasing.
Lightweight head.
New materials and designs helped protect the vehicle and
Data from destruction - head read / write "paryat" above the magnetic
carrier at an altitude of a few microns.
Linear drive heads read / write.
Due to the linear actuator is significantly reduced time for prospecting and transition