AS Level ICT: Hardware and Software

Task of an OS

*allocating* memory to software giving each task a *fair share of processor time* *sending* data and intstructions to *output* devices *responding* to *input* devices *Opening/Closing* files on storage devices *sending* error messages *logons and security*

Magnetic Tape Drive - Good?

*low cost*; high capacity (maybe several TBs); good for data stored and accessed sequentially

Video Editing Software FACTS

- a lot of processing time - a lot of RAM - importing takes time - encoding the final thing takes time

DBMS Features

-Data Entry Screens (FORMS) (to input data) -Filters and Queries (select data on criterea) -Reports (display info to easily read) -graphs (analyse data) -security features (only authorised access) -relationships (link related tables

Output options for graphics cards

-Video Graphics Array (VGA) through RGB port -High Definition Display through HDMI port -Digital Video Interface (DVI) which supports high resolution displays using digital signals

Spreadsheets

-calculations -modelling - financial and statistical info

Web Authoring Software

-common navigation bar -publish individual files or sites to server -preview -what you see is what you get / HTML view / Both - basic html like tables, lines, headings -manage metadata of webpage -designe templates -interactive features -forms and fields - validation of form fields`

Photo Editing Software

-crop -brightness -canvas resize -red eye removal -colour balance -cloning parts -magic wand --> identify common areas - effects (B&W or Sepia) -softening/sharpening

Video Editing Software

-import/capture video -clipping beginning/end -clipping sections -titles -overlaying, even with text -speed up/down -rotate -more than one video -transition between clips -background audio (music, narration) -picture in picture; two videos at ones

Word Processing

-letters -reports -coursework -menu -mail merging -books

Email Clients

-offline email reading -address book - signature -digital signature and encrypted messages - send and receive emails (duh) - delay sending - delivery/read receipts - rules for messages - multiple accounts - attachments -calendar integrations -inviting contacts to meetings in calendar

More uses of Storage Devices?

-programs stored on secondary storage ready to be loaded to RAM when program is opened - computers use secondary storage to save a virtual memory file to extend amount of RAM available (the virtual part of memory will be slow tho :/ )

Good things about Pen Drives?

-recognizable anywhere with a USB port -flash memory is very fast -no moving parts, so safe to transport -no magnetising, so no damage with a strong magnetic field

Cloud Computing Cons

Access time limited to bandwidth. Can be costly to store large amounts of data.

ADF

Automatic Document Feeder; allows documents with many pages to be scanned in one go

Types of Graphics Manipulation Software

Bitmap GMS Vector GMS

Sockets of a sound card?

Blue --> input for line level device. Red --> input for microphone green --> output for audio

Scanners

Capture 2D documents in image form

Storage Showdown: interoperability

Cloud> All (assuming HDD and SSD are external). Clouds can log in from any device. Others need USB port at minimum.

CLI

Command Line Interface; user enter text commands to which computer will respond in text format

User Interface

Communication between the user and the computer system

CD

Compact Disc; 700Mb storage. = 80 Minutes of Audio

Compilers

Converts *source* file into an *object* file, or executable. You can't go back to the high level code as it is now in a new format as an object file. Also, it will only work for the target OS or CPU.

Barcode reader

Detect width of lines and gaps that form a barcode, which represents some info and whatnot. QR codes store more data, which is why it can be used for pictures as well.

DVD

Digital Versatile Disc; 4.7GB

Printer Showdown: Running Cost

Dot Matrix are the cheapest, bc ribbon ink lasts a long time. Plotters and Inkjets have the same running costs, but plotters take more paper. However, LED plotters (usually B&W) are cheaper. Laser toners are higher priced than Inkjets, but last longer so price per paper is low.

Bitmap GMS

Fill *area* with colour move part of image resize part of image erase part of image clone part of image softening/sharpening image

Memory Card

Flash Memory on a small card; very portable; good for small deviced

Storage Showdown: Power

HDD > SSD > Pen Drive > Cloud HDD:need constant electricity SSD: only needed when in use Cloud: included in subscription charge Pen Drive: only needed when in use

Storage Showdown: Running Cost

HDD and Pen Drive may get damaged easily

HDD vs SSD: Cost

HDD cheaper

Storage Showdown: Uses

HDD: Desktop SSD: Laptop/Tablet Cloud: Collabs, back ups, sharing, general Pen Drive: Data Transfer

Cloud Computing Pros

Hosting company is responsible for security such as back up. Can be accessed anywhere, anytime, as it is stored remotely.

Why is MICR so effective?

Ink contains Iron Oxide which is easily detected by an MICR.

Printer Showdown: Colour

Inkjet and Plotter: YES Laser: Mostly monochrome. But colour is available. Dot Matrix: Rarely.

Interpreters

Instead of translating the whole source code, it translates one at a time. Less efficient and slower, but is useful when programs need to opened across various OS. Also used when testing programs as you don't need to compile the entire thing, so is faster on the fly.

Printer Showdown: Quality

Laser > Inkjet / Plotter > Dot Matrix. Laser melting it's toner and attracting it to the page is an advantage. Inkjets and Plotters have the issue of ink through thin paper and smudges. (Plotters w/ Pen makes makes the quality higher though) Dot Matrix: Bitmap nature causes issues.

Printer Showdown: Speed

Laser > Inkjet > Dot Matrix > Plotter. Inkjet is slower for colour, especially.

Printer Showdown: Typical Uses

Laser: Letters, *Bulk*, Home & Office Inkjet: *Photos*, Charts, Small Maps, Home & Office Dot Matrix: Receipts (bc carbon copy), ATMs, data logging, *hot/dusty environments* Plotters: Architectural Drawings, *Large Maps*, Canvas Prints, Signs

MICR vs OCR

MICR is used in checks because mistakes simply cannot be made. It is more accurate.

MICR

Magnetic Ink Character Reader. Used to print numbers at bottom of check.

Operating System

Manages the computer hardware. First thing to load after BIOS (basic input/output system)

Sound Card?

Often integrated into motherboard. To send signals from computer to speakers

OCR

Optical Character Reader. Scanner with software to recognize characters on document, so can be searched/edited

OMR

Optical Mark Reader. Detects marks in a MCQ exam.

Optical Storage vs Tapes

Opticals have less capacity; but can have data accessed directly

Word Processing Features

Other than the obvious (tables/footnotes/spellchecker...): frames for imagers automatic contents page tracking changes text wrap

Printer Showdown: Cost of Purchase

Plotter$$$$ (bc size) > La$$$er > Dot Matrix (only because they aren't ma$$ produced anymore) > Inkjet (also the worst kind of printer. Don't buy them.)

Mouse

Pointing device that allows objects to be selected or manipulated on the screen

System Software

Programs designed to maintain or operate a computer system compilers, linkers, device drivers, operating systems and utilities, interpreters

Application Software

Programs intended to carry out a task for the user

Storage Showdown: Cost

SSD > HDD Cloud: Subscription, so depends. Pen: Depends on size

Storage Showdown: Speed of Access

SSD > HDD HDD: depends on SATA connection Cloud: depends on broadband bandwidth offered by user and supplier Pen Drive: Depends on whether USB 2 or USB 3

HDD vs SSD: speed

SSD faster

HDD vs SSD: Power

SSD takes less power, so is used in tablets and high end computers for more battery life

SSD vs HDD: Power

SSD uses less power

Formats of Memory Cards

Secure Digital (SD) MicroSD

but...? (Pen Drives)

Size means that it can get lost. External HDDs can store more data

Advantages of Blue Ray Discs

Storage (25GB; 50GB on dual layer); Possible to by recordable and rewritable ones cheaper than getting a whole HDD

Types of Software

System Software Application Software

Magnetic Tape Drive

Uses: Back up and Archive of Data. *SERIAL STORAGE*

Communications Software

Video/Audio Conferencing Email Clients (as opposed to webmail)

Storage Device

a device used to store data onto a storage medium

Device

a hardware component of a system that contains electronic components

Storage Medium

a medium on which data is stored

Hardware

a physical component of a system

Graphics Card?

aka Video Card. Printed circuit board connected to one of motherboard's expansion slots. generates signals needed to display the output image from the computer.

Webcams

camera connected to computer. Not as good quality as a dedicated digital camera. Usually has integrated microphone for capturing sound

Portable Hard Disk Drive

can be connected using a USB or External Serial Advanced Technology (eSATA) port. Susceptible to damage due to moving parts and magnetizing.

Inkjet Printers

cartridges of ink, "squirts" them to form images

Laser Printer

charges a cylindrical drum; attacks electrically charge toner, toner is heated so it melts onto paper

Device Drivers

comes with an external hardware component and sends customised instructions to that specific component

Volatile

data *lost* when there is no power. Like RAM

Non-volatile

data *remains* when there is no power. Like ROM

Magnetic Tape Drive - Sucks?

data access speed is slow; needs to be wound to exact position so is unsuitable for everyday use

Input Device

device that allows data to be entered into a computer system

keyboard

device that consist of buttons which are used to input text or control part of the interface. Ergonomic ones can help with RSI btw

Output Device

device used to communicate data or information *from* a system

Both GMSs can...

draw shapes change canvas size change image size add layers add text (to image) select a colour based on picking an existing colour :)))

Vector GMS

fill *shape* with colour change features of shape borders (thickness, colour, etc) combine shapes in groups moving said shapes (or groups) resizing said shapes (or groups) align objects

Blue Ray Disc Drive

like a DVD or CD, but can store HD video. Up to 25GB storage. Dual layer can have 50 GB!

Linkers

link object files together to form a single executable, as many modules of one program will have it's own object file

CLI - Good?

little memory so good in old systems maintenance of small systems to carry out complex operations

Monitor FACTS!!

many are flat screens. some can have touch screens. that is all. :)))

Disadvantages of Blu Ray

needs a Blue Ray disc drive; much slower data reading speed than a HDD

HDD Features (Hard Disk Drives)

non volatile moving parts (vulnerable to damage if dropped) magnetic

SSD Features

non volatile (duh) no moving parts non magnetic

USB Flash Drive

or "Pen Drive"

Software

programs which give instructions to a computer

Dot matrix Printers

set of pins driven on to a ribbon, then ink is transferred to paper

Applets

small program; can't run on it's own; must be executed from other software; like add-ons; carry out additional tasks; or simplify tasks

Compilers and Interpreters

translates a program written in high level programming language like C++, into machine code which a computer can understand

Database Management Systems

used for viewing and editing data within a database

UI

user interface is boundary between user and computer system

Uses of Storage Devices (Secondary Storage)

user may want to: - make changes to document in future so saves it in one - someone else to edit said document so saves it in on - keep document for archive and future referral so saves it in one - save each new or changed record to a database in a secondary storage so saves it in one - back up data so a spare copy is there so saves it in one

Photo Editing Software FACTS

uses a lot of RAM; complex operations use up a lot of processing time

Plotter

uses pens to create vector drawings

Control and Measuring Software

we've done this before -,-

Cloud Computing

where computing services are hosted over the internet and not the same physical location where the computer is being used.

SOmething about runtime library

will add later