| what is operating system | provides both the environment in which applications can be run and a useable interface between human and computer |
| why do you need to do a horizontal and vertical parity check at the same time | so you can know where the wrong bits are |
| why is just a horizontal or just a vertical parity check insufficient | you only know there is an error, not where it is |
| What is echo check | An error detection method where a copy of the data is sent back immediately, if it's not the same, then the original data is sent again |
| what is the disadvantage of echo checks | you cannot tell if the error was sent during the original transmission, or during the sending of the copy |
| what are the two most common errors when transmitting data | packet switching, interferance |
| what is a checksum | an algorithm calculates a checksum value from the data sent, the same algorithm is used the the receivers side. if they are the same then there is no error, if they are different, then a request is sent to send the original data again. |
| What is check digit | All numbers of the code go through an algorithm to get a check digit, once it goes through the algorithm again and the resulting number divides into 11 without remainders, then the number is valid |
| What is the process of finding a check digit | Weighting, multiply, addition, remainder, subtraction |
| What happens after the check digit is found | Gets weighting (at the right) then added to the original addition, then that number is divided by 11. If there is no remainder then the number is valid |
| What is an error detection code also known as | Cyclic redundancy check |
| What happens when acknowledgement isn't sent back to the sender in an Automatic Repeat Query | Timeout occurs, the sender then sends the data again, until either an acknowledgement is sent back, or a preset number of sendings is met |
| What happens in ARQ | Automatic Repeat Query. When data is sent, an error detection code is also sent. The receiver then sends back a positive or negative acknowledgement. If negative, the sender sends the data again. |
| what is syntax highlighting | Colored text based on the type of code AND automatically highlighting errors in code |
| what is error checking | IDE automatically finding errors in a program |
| what is IDE | Integrated development environment. Text editor with features to help programmers |
| What is pretty printing | Automatic spaces and indentations which make code easier to understand |
| what is translator in IDE | Translating high level language to low level language for the computer to understand |
| what is run time environment | software that allows any program to be run on a computer |
| 11 Features of IDE | Syntax highlighting
Error checking
Line of code
Collapsing line
Inputs/outputs
Autocompletion/correction
Pretty printing
Translators
Run time environment |
| what is fixed program computer | a computer that can only perform one task (eg, calculator) |
| what is a stored program computer | a computer that can use many programs |
| What is CPU | Central processing unit. performs fetch decode execute cycle |
| What is CU | Control unit. reads instruction form memory |
| What is ALU | Arithmetic logic unit. Does arithmetic (+-/*). Does logic gates (AND NOT OR etc) and comparisons between values (<>=!=) |
| What is PC | Program counter. Holds the memory address of the next instruction. |
| how many bits in 1 byte | 8 |
| what is operating system | provides both the environment in which applications ca be run and a useable interface between humans and computer. |
| what is cache | memory that is in the CPU itself, it is the fastest to access. stores commonly used instructions and data. Improves Cpu performance. |
| what is the purpose of a web browser | software that allows users to access web pages by interpreting HTML to show what is on the website |
| features of web browser | HOme page
Bookmarks/favourites
History
Navigating forward/backward between past websites
Cookies
Tabs
Hyperlinks |
| benefits of compression | reduced file size. can fit within file size limits. faster file transfer. less bandwidth needed to transfer files. |
| examples of primary storage | RAM ROM |
| examples of external secondary storage | HDD SDD DVD memory stick, blu ray stick, removable hard drive |
| what is primary memory | directly addressable by the CPU.
contains RAM ROM and cache memory |
| What is secondary storage | Not directly addressable by the CPU.
All non volatile
Can be external or internal
can be optical, magnetic, or solid state |
| examples of internal secondary storage | HDD SSD |
| features of ROM | storing factory settings
storing start up routines
storing set routines (eg, buttons on a controller for turning left, right, stop) |
| what is SSL | Secure socket layer. Makes the website secure by establishing an encrypted link between the server and client computer. It is identified by the "S" at the end of HTTPS |
