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