Seeram Chapter 2: Introduction to Computers
Post on 12-Jan-2016
54 Views
Preview:
DESCRIPTION
Transcript
CT
Seeram Chapter 2:
Introduction to
Computers
Electronic Computer Technology
Vacuum tubes
Discrete Semiconductors
Integrated Circuits
Early Computers1951-1958Vacuum tube memoryInput / Output
Punch cardsMagnetic Tape
Electronic Computer Technology
Warm-upRan hothot
tube filaments required constant heating
computers required air conditioning
Frequent failures
Computers after Vacuum Tubes1959-1963Transistor & magnetic
core memorySmallerLess power needed
Discrete Semiconductor Components in Computers
transistorsmagnetic memory coresSpace requirements
largebut
smaller than vacuum tubesRan much coolercooler than vacuum tubes
Computers: The Big JumpIntegrated Circuits
millions of semiconductor components in tiny packagelower production costs
Extremely smallExtremely fastRun very coolVery reliable
Categories of Computers
Super computers
MainframesMinicomputersMicrocomputers
5th Generation: Supercomputers
Large (even today)ExpensiveFound only in major research sitesApplications
weatherscientific modelingoil explorationother research
Mainframe ComputersLarge$$$Requires teams of expertsLarge # of usersApplications
large corporationsgovernmenthospitals
Microcomputer
“PC”Rapidly changing
technologyLow costNon-proprietaryFirst common in
1980’s
MinicomputersFirst seen in 1970’sMuch less expensive than mainframesMedium-sizedProprietary ($$$)
partsoperating systems
Computer used for CTAppropriate
Size price
Applications imaging, reconstruction archiving
Basics
Input Processing Output
InputManual
keyboardmouse
ElectronicCT detectorsCR Plates
Input Processing Output
Other Voice
recognition
Analog to Digital Conversion(A to D)
Analog(continuously varying)
Digital(discretely varying)
Analog to Digital Conversion(A to D)
Many real world inputs are analog voltagesCT detector intensity
Analog values must be converted to a # to use in a computer
0.2
0.4
0.6
0.8
Input analog voltage
1 2 3 4Digital conversion
to computer
ProcessingCentral Processing Unit (CPU)
ArithmeticLogic
Internal MemoryScratchpad
Input Processing Output
OutputHard copy
printerSoft copy
CRT
Input Processing Output
Storage• disk• tape
Hardcopy DevicesDo not lose information
when power is shut offPrinters
impact (dot matrix) noisy multi-copy
non-impact (quiet) ink jet laser
PlottersMicrofilm
Softcopy DevicesLose all information
when power shut offFlat-panel monitors
Digital to Analog Conversion(D to A)
Computer reconstructs digital imageset of numbers
Computer displays analog image
125 25 311 111 182 222 176
199 192 85 69 133 149 112
77 103 118 139 154 125 120
145 301 256 223 287 256 225
178 322 325 299 353 333 300
Computer System Elements
Hardware Software
People
Hardware
ComputerPeripherals
keyboardprinter
Hardware Software
People
HardwareExamples
Disk DriveMemory
Random Access (RAM)
Read only (ROM)
MouseKeyboardCables
Hardware Software
People
SoftwareInstructions to computer
Operating SystemApplications
Hardware Software
People
Operating System
Fundamental instructions to hardwareWhat to do when computer first turned onHow to interact with hardware
CRTKeyboardMouseModem
Hardware Software
People
Operating SystemComputer “face” presented to users
WindowsDOSMAC OS
Dictates how usersinteract withcomputer torun applicationsoftware
Hardware Software
People
Application SoftwareComputer instructions which perform
some desired taskBalance checkbookPlay a gameCalculate (reconstruct)
a CT image
Hardware Software
People
Application SoftwareUsually a quasi-quasi-
EnglishEnglish languageBasicFortranCOBOLC
Languages provide tools to software developers to efficiently design application software
Forms![FDoSurvey]![FExpsSub].Form![KVEff] = Val(Mid$(MyData, 2, 10))Forms![FDoSurvey]![FExpsSub].Form![KVAVG] = Val(Mid$(MyData, 12, 10))Forms![FDoSurvey]![FExpsSub].Form![MRMEAS] = Val(Mid$(MyData, 22, 10))Forms![FDoSurvey]![FExpsSub].Form![TIMEMEAS] = Val(Mid$(MyData, 32, 10))DumText = Mid$(MyData, 42, 3)'MsgBox$ (DumText)If Right$(DumText, 1) = "+" Then DumText = Left$(DumText, 2)Else DumText = Left$(DumText, 1)End If'MsgBox (DumText)MyData = Right$(MyData, Len(MyData) - Len(DumText) - 41)'MsgBox (MyData)NKvs = Val(DumText)'MsgBox (NKvs)KVMAX = 0If NKvs > 0 Then For DumNum = 1 To NKvs 'MsgBox (Val(Mid$(MyData, 10 * (DumNum - 1) + 1, 10))) If (Val(Mid$(MyData, 10 * (DumNum - 1) + 1, 10))) > KVMAX Then KVMAX = (Val(Mid$(MyData, 10 * (DumNum - 1) + 1, 10))) End If NextForms![FDoSurvey]![FExpsSub].Form![KVMAX] = KVMAXEnd IfDoCmd.Close acForm, "FNeroExp"End Sub
PeopleDesigners
hardwaresoftware
Usersrun applicationsprovide inputuse output
Meaningless Slide
Storage HardwareRandom vs. Sequential
Direct (random) accessany data can be accessed at any timedisks
Sequential accessdata only accessed in serial fashionmust pass through unwanted data to reach
target datatapes
information encoded magnetically
Data Storage Technologies(constantly changing)
DisksFormats
Hard removable non-removable
Floppy CD
CD-RW CD-R
Tapelots of dataserial access
Technologies» Magnetic (disks & tape)
re-writable
» optical (disks & CD’s) re-writable write once
Data Communication
Featuresspeedcosttopology
wiring scheme
Data transmission between computers
Data Communication Technologies
Telephone linestwisted pair wires
Coaxial cableFiber optic cableMicrowavesSatellitesRadio waves
NetworksLAN (Local area network)
computers connected in one areaLAN’s can be connected together
WAN (Wide area network)computers connected together over large
distancesCommunications protocols
Ethernet uses bus technology
Internet
File ServerSpecial computer which handles functions
for connected computersdisk accessprinting
Incorporates securitymay limit user to selected files or directoriesmay limit # of connections per usermay limit times when network available
Typical Lan
NetworkGateway
OtherNetworks
Radiology Computer Systems
RIS
Professional
Billing
CR
CTMRI
Digital Dictation
Mammography
Digital Spot Film
Voice to TextDictation
WebServer
InsuranceCarrierHospital
Admission/Discharge
Billing
Reports
PACS
Angio / Digital
Subtraction
The Computerization of Radiology
RIS PACS
CT CR MRIDigitalFluoro
DigitalAngio
Dictation Admin
RadiologistWorkstation
RadiologistWorkstation
RadiologistWorkstation
3DWorkstation
NucMed
LaserPrinter
Web Browser
The Internet
Network connecting all computersOriginally developed for security
Single bomb can’t destroy all U.S. computing facilities
Can connect large number of computers in many locations
Communicates in finite “packets”Each packet has specific destination (address)Packets can be
E-mail Web site
Allows linkinglinking of information
top related