RAD 350 Chapter 14 Computers in Medical Imaging
Important dates:
1939 first electronic computer built
1944 first general-purpose “modern computer” developed
1946 first “general purpose-electronic” computer developed
1948 transistor developed
1951 UNIVAC commercially successful computer
Digital vs analogue
Digital is electronic impulses that can be transmitted across wires or atmospheric conditions (anywhere ELECTRONS can flow) AND only TWO values / on-off or 1-0
Analogue – multitude of varying quantities
Types of computers:
Super computers, mainframe computers, WORKSTATION, MICRO/MINI computers
Hardware:
Input – keyboards, pointing devices and source-data devices
Processing – central processing unit (CPU), control unit and arithmetic/logic unit (includes memory)
RAM - random access memory
ROM – read only memory
BIT – smallest unit of measure memory
BYTE – 8 bits = 1 byte
RAID – redundant array of inexpensive disks*** (has been defined differently in varied texts!
OPTICAL DISKS (have replaced mag tape/floppies, etc.)
CD-ROM = read only memory
CD-R = write data – can only be used once!
CDE/CD-RW = allows user to erase and re-write on the CD
DVD-ROM = digital versatile disk = read only memory
OUTPUT DEVICES
Usually display screens and printers, etc.
-Others: plotters, multifunction devices and audio output devices
OUTPUT HARDWARE- devices that TRANSLATE computer information to a form that
mere humans can understand
Transmission speed (modem transfer in bits/second = BPS)
Integrated Services Digital Network (ISDN) – dial up modem
Digital Subscriber Lines (DSL) much faster than ISDN, but still can be done via phone lines
SOFTWARE – written in computer language so the hardware can function and do what we want it to do
-Binary numbers/switches – either 1/0 or on/off
LANGUAGES: FORTRAN; COBOL, ALGOL, BASIC, BCPL, B,C (be familiar with these as they are often on the boards – not what they do or how they work – just that they are “languages”
PROCESSING METHODS: (does PACS ring a bell?)
Batch – without needing human input to perform
On-line = done on-line and immediately
Time-sharing = makes one think he/she is the “only one using the system”
Real-Time = instant/fast management of the system hardware