Mainframes and Supercomputers

Mainframe Computers

• Large, powerful computers exceeding normal computers in processing power
• Can serve numerous terminals
• Utilize parallel processing
• Operate as multitasking, multi-user systems enabling multiple users to collaborate on various problems concurrently
• Include hundreds of processor cores sharing an operating system

Supercomputers

• Use massively parallel processing
• Capable of rapidly completing highly complex tasks
• Can have more than 100,000 processing cores
• Each core has its own OS
• Use more than one GPU (Graphics Processing Unit)
• Primarily execute a few computer programs
• Focus on rapidly executing instructions for single purposes to maximize capacity

Longevity of Mainframes and Supercomputers

• Mainframe computers have great longevity
• Can run continuously for long periods with minimal downtime
• Turning them off and disposing of their hardware is very expensive
• Designed to last for decades and remain functional
• Supercomputers typically last about 5 years
• Often used by organizations like meteorology until a faster supercomputer is available

RAS (Reliability, Availability, Serviceability)

• Pertains to mainframe computers
• Reliability: Processors can check themselves for errors and recover without adverse effects
• System software is reliable due to thorough testing and quick updates to fix errors
• Availability: Mainframes are available for extended periods
• Mean Time Between Failures (MTBF) measures the average time between downtimes
• Downtime is short due to quick recovery from spare components used automatically upon failure
• Serviceability: Ability to detect the cause of a failure and replace hardware/software components with minimal operational impact

Security

• Mainframes have greater security than other computer systems
• Includes multiple layers of security
• User identification and authentication using multi-factor authentication
• Access levels which limit the data users can view based on their security level
• Encryption of data in transit and within the system
• Secure operating systems
• Continuous monitoring for unauthorized access
• Supercomputers use end-to-end encryption to ensure only the sender or recipient can decrypt data vital for storing sensitive data

Performance Metrics

• Performance metrics measure processor efficiency
• Mainframe CPU speed is measured in Millions of Instructions Per Second (MIPS)
• MIPS is not always the best measure since instructions vary in complexity
• MIPS is linked to cost by calculating mainframe cost per million instructions per second
• Supercomputers use FLOPS (Floating Point Operations Per Second) measuring floating point operations for scientific calculations
• Modern supercomputer performance is measured in PetaFLOPS/Quadrillions of FLOPS
• FLOPS can be unreliable as they don't account for CPU clock speed, bus speed, and RAM

Volume of Input, Output, and Throughput

• Mainframes have peripheral processors to manage input/output, allowing the CPU to focus on data processing
• Enables mainframes to handle large data inputs, records, and outputs like billions of transactions per day
• Throughput refers to the volume of simultaneous transactions and input/output in a given period
• Supercomputers are built for processing power and speed, while mainframes excel in throughput

Fault Tolerance

• Fault-tolerant computers continue operating even if components fail, possibly at a reduced level
• Mainframes are fault-tolerant in hardware
• Automatically switch to another processor if one fails, without disrupting data processing
• Same can be done with a software error by running one of two versions of a software
• Supercomputers have more components than mainframes, making failure and interruption more likely
• Fault tolerance for supercomputers is similar to mainframes
• System may go down but recovers quickly

Operating System

• Mainframes run multiple operating systems at once
• The OS divides tasks into subtasks and assigns them to processor cores
• Results are combined to provide meaningful output, this is called parallel processing
• Supercomputers often use one OS
• Use massively parallel processing, with each processor core having its own OS

Processor Type

• Early mainframes had a single CPU
• Modern mainframes have multiple CPUs
• Called CPU complexes
• Mainframes have hundreds of processor cores
• Supercomputers have hundreds of thousands of processor cores
• Modern supercomputers use more than one GPU, unlike mainframes

Heat Maintenance

• Overheating is a major problem for both mainframes and supercomputers
• Older mainframes used liquid cooling systems, while 1980s models used fans
• Modern mainframes use powerful hardware, making air cooling complex and expensive
• Water cooling is now more cost effective
• Supercomputers always have overheating issues, which affects component lifespan
• Supercomputers consume enough megawatts to power several thousand homes
• Direct liquid cooling is required

Mainframe Computer Uses

• Used for the census
• Official population survey to determine how many people live in a country
• Used to get details such as ages and types of employment
• Census data size makes mainframes essential
• Census data size increases every ten years
• Used for Transaction Processing
• Consists of multiple computer processing operations that combine to make a single transaction
• All operations must be error-free
• Otherwise the transaction is deemed failed

Transaction Processing (Continued)

• The transaction processing system will remove all traces of the operations and the system will continue as thought the transaction never happened
• If the transaction is successful, the database is updated before the system continues onto the next transaction
• Effectiveness is measured by transactions processed in a given time period, using MIPS
• The system must be available during transactions
• Must be able to cope with hardware and software problems
• Able to add, replace, or update hardware and software without shutting down
• With the ability to transfer processing from one core to another the mainframe is highly suitable for this task

Industry Statistics

• Statistics on trends in industries processing raw materials, manufacturing, or providing services
• Needed for industries processing vast amounts of data to identify competitors
• Show market share and sales trends of competitors to identify potential profitable products
• Obtained from organizations collecting data, require use mainframes

Consumer Statistics

• Allow businesses to assess product demand
• Provides range of household incomes and employment status of consumers to determine potential product pricing
• Provides information for major consumer geographical locations for sales, or online shopping inclination
• Provides knowledge of similar products available and their prices
• Produce vast amounts of data requiring the use of mainframes

Supercomputer Uses

• Used for Quantum Mechanics
• Studies the behavior of matter and light on the atomic and subatomic level
• Describes the properties of atomic components
• Requires accurate and numerous calculations
• Used for Weather Forecasting
• Uses complex computer models with data from weather stations worldwide
• Stores records of previous weather conditions for very long periods
• Examines weather patterns to predict outcomes
• Records atmospheric pressure, humidity, rainfall, wind, and direction
• Uses data together with radar satellites for a 3D model of the Earth's atmosphere
• Limited to supercomputers

Climate Research

• Extension applied to weather monitoring with IT
• Measures climate over long-term scale, collecting data for decades
• Shows trends in variables like nitrogen dioxide, ozone, and sulfur dioxide
• Research Earth components like animals, humans, volcanoes, weather, and sun heat
• Variable data collected and complex calculations are needed
• Supercomputers run models of interactions between components of climate systems
• Used for climate research that include atmosphere, land, ocean, and ice models with equations to mimic climate change

Advantages of Mainframes

• Very reliable with rare system downtime
• Hardware and software upgrades can occur while system is running
• Becoming faster and more powerful each year
• Outperform PCs, laptops, and other devices
• Able to store and process data
• Able to cope with data coming in a variety of database formats
• Have stronger security with complex encryption and authorization procedures

Disadvantages of Mainframes

• Expensive
• Only affordable by large organizations such as multinational banks
• High cost for personnel
• Need large rooms to house the system

Disadvantages of Mainframes (Continued)

• Recent mainframes need heat maintenance, cooling systems are complex and costly
• Software is more expensive
• Many organizations are shifting to cloud services
• Don't need to hire expertise for them
• Advantages of Supercomputers
• Fastest data processing computers
• Use massively parallel processing
• Process with far fewer processors core than mainframes or supercomputers
• Disadvantages of Supercomputers
• Expensive to buy and install
• Only have one operating system
• Where mainframes may have more than one
• Are less fault tolerant
• Can't recover as quickly if a component fails
• They are down more often than mainframes but not as often as other systems

System Software

• Refers to the programs that control a computer's hardware and application software

Compilers

• Computer programs that translate source code (high-level language) into executable object code
• Translate the whole program in one complete unit
• Produce an executable file that can be run without the compiler
• Provide a list of errors to help debug the program
• Errors can't be corrected without going back to the source code
• Requires that the program be recompiled after debugging

Advantages and Disadvantages of Compilers

• Advantages: Do not have to be translated again; can run much faster than interpreted software
• Compiling is quicker; source code translated into machine code is more difficult to understand and improves security
• Produces an executable file and doesn't require a compiler to be at run time
• Disadvantages: Programmer must wait during compilation to correct errors
• Output error list can make finding errors tricky and requires recompilation
• Compiled program can only run on computers with the same OS; compilation takes more memory than interpreting
• Doesn't allow small pieces of code to be tested
• More likely to crash the computer
• A cross compiled program can run slower on target machine

Interpreters

• Translate high-level language programs one statement at a time into an intermediate form
• Executes that line before moving onto the next one
• Report errors as lines of source code are processed
• The error has to be corrected before it can continue working on the next instruction
• Requires to be resident in memory for the program to run
• Needs little program memory at any one time saving memory space
• Can be transferred between computers with different OS because it remains in source code

Advantages and Disadvantages of Interpreters

• Advantages: Able to execute each statement as it is entered
• Generate helpful reports useful during program development
• Debugging is easier with error messages provided immediately
• Interpreted programs are written in source so can run on any system with an interpreter
• Uses less memory and allows small pieces of code to be tested
• Can run partially complete programs
• Disadvantages: Execution process is slower
• Source code must be available which can lead to software copyright infringement
• No executable file is produced
• Interpreter needs to be present during run time

Linkers

• System program that combines compiled object files or modules into a single executable file
• Replace symbolic addresses with real addresses
• Help simplify development by joining these modules back into a single program file
• Larger programs can be compiled in small parts because of space limits in RAM
• Parts can be stored on backing storage and compiled one at a time
• Resulting object code can then be saved to the backing storage
• Brings object code into RAM one piece at time
• Advantages
• Less RAM for programs
• Programs need separate modules which saves programmer time
• If there is an error in the code only that module has to be corrected
• Disadvantages
• Could be problems with different variable names being used for the same variable in different modules
• Documentation also has to be more detailed and takes longer to write or read when completed

Device Drivers

• Small program that allows the OS and software to communicate with hardware
• Controls the device connected to the computer
• Examples include printer drivers, mouse drivers, and keyboard drivers
• Detects and identifies peripheral devices upon installation
• Wakes up the device when it is needed and puts it back to sleep when it is not needed
• Handles the translation of the request
• Defines where outgoing data must be stored before it is sent
• Act as interface between the operating system and the printer
• Required printer driver, the printer fails to work as the software used by the computer tends to be created by different companies to those that manufacture printers
• Needed to convert the instruction set so the software is able to communicate with the hardware

Operating Systems

• Software that manages computer hardware and software resources
• Interact with device drivers
• Act as interface between user and computer
• Supply important utilities for managing the computer
• Stored on the hard disk but the instructions for loading the OS stored on ROM
• Executed when the computer is switched on
• OS is an interface between an application program so it can communicate with the hardware
• Manages computer shutdown
• Safely closes all software before turning off power
• The OS Manages and allocates memory to software to make sure instructions and data don't corrupt data
• Transmit data to printers, manages output data and communicates with drivers

Operating Systems (Continued)

• Provides interface with the user, opens/closes files, allocates time

• Sends error messages, handles logins, and calculates/compares password data to allow user access, and file permissions

• Multitasking OS = System has more than one processor

• A Single OS can divide tasks into subtasks

• Multiprogramming = System allows more than one program to run

• Interpreted program will work on any system but must have the correct OS

• High level languages can be interpreted

• Languages which can be compiled use a cross compiler which can be small versions compiler used on host or native computer

• Compiled programs using Cross compiler, won't run the computer program runs on/host computer

• Cross compiled programs run slow and produces more errors

Utility Software

• Assists users to manage system operations
• Managing computer memory is requires to improve performance, and customize their desktop
• Keep computers free from viruses and keep files contiguous.
• The OS includes different utilities
• Sector is the smallest unit of hard-disk storage
• Block: Logical data sector unit is composite of many storage
• Track concentric circles a in disk storage organizes the sectors

Utility Software: Hard Disk Structure

• Hard disks are Individual disks consist of several platters. All surfaces of all platters have their own head
• The disk platters are stacked in the same direction along with speed
• The read write disk platters moves the surfaces. Does not touch the disk, is to read or store data at the storage
• The surface of each disk is then split into tracks, form a cylinder on each disk at track
• Split in to sectors, is written from the outside in

Utility Software: Disk Storage, Terms, Disadvantages

• When cylinder is filled read write hands move in to the disk.
• Signature based virus detection only detects known threats and can create false positives
• Disadvantages of Anti Virus:
• Signature based is only capable of detecting known viruses.
• New unknown viruses can severely damage a hard disk
• Heuristic based methods create false positives when algorithms match files that don't contain viruses

Disk Defragmentation

• Data stored on a disk consists of blocks not next to each other
• Empty sectors are sectors in between data
• Data divided is fragmented from data disks
• All fragments of segments of disk, it can be contiguous
• As result data retrieval is quick
• Attempts too create space in free space
• Moves to find all the different sequence of files
• The disks are held in a sequence
• Provides data frees space and storage capacity

Formatting

• Configures medium for initial use.
• Low Level = Divides disk to tracks and cylinders. Done by magnetizing disk. Tracks start numbered from 0. When the head goes to the next track it leaves a gap
• Each track is then separated in to numbered sectors
• The purposed of low level to prepare the disk receive and save data
• High Leve = Generates a file that allows space to store and access files
• Does not erase data
• Just deletes the files and where the files find it

Formatting Continued

• Advantages:
• Formatted disks scan remove viruses.
• In high level files are still retrievable
• Disadvantages:
• Individuals carrying out file formatting rather the manufacturer have difficulty formatting data. Reduces life in medium.
• In low level formatting file aren't retrievable

Anti-Virus

• Detects and removes viruses.
• Prevents computer attaching from virus and marewares.
• Anti-Virus software needs to be up to date because new worms are made frequently and Anti-Virus will not detect them
• Either removes or quarantines ask user needs remove files
• Anti-Virus can performs a background scans and scans the whole disk and in form user

Anti-Virus (Continued)

• Uses the following approaches
• Signature Based: recognizes exiting viruses.
• The code is added to the database ( compares is against is to database).
• Heuristic Based: Detects marewares based a characteristic
• Behavioral Based Detection: Looks for abnormal behavior such large amounts of emails
• Sandbox Detection: Based on a behavioral analysis. Executes virtual code in to a run time and does real harm

Backups

• Software that keeps saved copies of files
• Duplicates of files
• Can be used for restoring file corruption
• Software allows the user to select the time and and where to store the date
• The user set up automated backup processes

Backups Continued

• Back ups are stored on devices and clouds
• Can perform incremental backup where after change specific date
• A differential differential back up the saves the has back up
• Store verify make sure that backup mates
• Store to ensure the back is not

Data Compression

• Modifying data so it occupies less storage.
• Can be lossy or lossless.
• Compression files this removes can be over come listed as redundant
• Lossless returns to its own state
• Repede bits replaced by a character along.

Data Compression (Continued)

• The original is smaller.
• Text is replaced by origin compression used with spread sheet and data bases to remove a huge lost.
• Loss compression repeated bits are permlike left effect which has little effect.
• Image files with high compress
• Advantage:

• Is transferred faster over the internet.
• Saves storage it reduces code an time
• H. D vids

Data Compression DIsadvantages/ File Copying

• Disadvantages
• Data compressors
• Loading takes longer
• Slightly lowered
• Copy file copy existing file and content, copy in disks systems, folder and directory and create tow versions the same file

Deleting

• Tell were to delete it
• Moves that file to trash
• To delete and is free ready for use
• A file recovery software can see the hard drive

Custom-Written Software

• Software written for a specific task that is developed for a specific company
• Made form and scratch and owned by the license
• They find someone to write the that software that fixes program or meats the companies specifics.
• Support can be got from the the business who made the software
• DIsigned for task and no is an unnecessary code

Custom-Written Software Advantages and Disadvantage

• DIsigned for task and no is an unnecessary code

• The program does not need too be adapted for for use

• Programmers are always there to make modifications.

• Always compatible with what is already there

• Company own all cop rights so can see it too.

• Can has less storage then a shop software

• Disadvantages:

• Cost to pay programmer to write code needs

• Needs to make too what the program might needs

• Only has the team of programmers

• Long time spent develop

Off-the-Shelf Software

• Software reads made and ready to use
• Owned by the company that made don't have right's sells it
• Its be adpated business needs and preen and don't needs that company can to others
• Has a lag amount of unneed storage
• Relatively cheap compare it to write to custom

Off-the-Shelf Software (Continued)

Advantages

• Cheaper
• Will get it straight away
• Be run thoroughly without too many bugs.
• Lots amounts support lines support DIasvantes
• Has to be adaped user needs that need and it be compatible customer
• Migh have alot unnecessary features
• Incompaitle system

Proprietary and Open Source Software

• Proprietary Is the company the owner license, us code is usually always used by the and encoded and copyright
• Open stores all users the data Is easier data but the computer has compatibly. Has always is files

User Interface

• Is the the system connects to with the computer input with the computer system or

Command Line Interface

• Interacting terminal
• A prompt on screen after after is enter.
• Requires fewer rescores than gui. Its key no mouse is needed Advantages.
• Processing data is fast
• Less likely change easy for all

Command Line Interface Advantages and Disadvantages

• Disadvantages
• Can be used key bad. Is only used by doctors
• Is is a long line a code
• Too have and learn lot to and to

Graphical User Interface and Dialogue Interface

• The pointers

• Has button is made for.

• Disadvantages

• User with it is hard mouse and needs is Too hard to get on old

• Dialogue Interface:

• the uses with has the use. The can listen and

• It needs to