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Information and Communication Technology Applications

Today’s fastest supercomputer operates at a speed of about 35 teraflops, that is 35 trillion floating
Notes point operations per second (a floating point operation is a mathematical operation, such as
multiplication or division, on two high precision numbers). 35 trillion (35,000,000,000,000) operations
per second sounds like a lot (it actually blows your mind), but you may be surprised that your new
desktop computer from Walmart is only about 1000 times slower. That is, if you get 1000 of them to
work together efficiently, you have a supercomputer. And that is exactly what many research
institutions have done: putting together clusters of Linux based computers running on high
performance Intel processors to obtain an affordable supercomputer.

What do you mean by classification of computer? Explain it.

Mainframe Computer
Mainframes (often colloquially referred to as “big iron” are powerful computers used primarily by
corporate and governmental organizations for critical applications, bulk data processing such as
census, industry and consumer statistics, enterprise resource planning, and financial transaction
processing.
The term originally referred to the large cabinets that housed the central processing unit and main
memory of early computers. Later the term was used to distinguish high-end commercial machines
from less powerful units.
Most large-scale computer system architectures were firmly established in the 1960s. Several
minicomputer operating systems and architectures arose in the 1970s and 1980s, which were known
alternately as mini-mainframes or minicomputers; two examples are Digital Equipment
Corporation’s PDP-8 and the Data General Nova. Many defining characteristics of “mainframe”
were established in the 1960s, but those characteristics continue to expand and evolve to the present
day.
Description
Most modern mainframe design is not so much defined by single task computational speed, typically
defined as MIPS rate or FLOPS in the case of floating point calculations, as much as by their redundant
internal engineering and resulting high reliability and security, extensive input-output facilities,
strict backward compatibility with older software, and high hardware and computational utilization
rates to support massive throughput. These machines often run for long periods of time without
interruption, given their inherent high stability and reliability.
Software upgrades usually require resetting the Operating System or portions thereof, and are non-
disruptive only when using virtualizing facilities such as IBM’s Z/OS and Parallel Sysplex, or Unisys’
XPCL, which support workload sharing so that one system can take over another’s application
while it is being refreshed.

Mainframes are defined by high availability, one of the main reasons for their
longevity, since they are typically used in applications where downtime would
be costly or catastrophic. The term reliability, availability and serviceability (RAS)
is a defining characteristic of mainframe computers. Proper planning and
implementation is required to exploit these features, and if improperly
implemented, may serve to inhibit the benefits provided.

In addition, mainframes are more secure than other computer types. The NIST National Institute of
Standards and Technology vulnerabilities database, US-CERT, rates traditional mainframes such
as IBM zSeries, Unisys Dorado and Unisys Libra as among the most secure with vulnerabilities in
the low single digits as compared with thousands for Windows, Linux and Unix.

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