January 20071R. Smith - qmcs 200 QMCS 200 Lecture

January 20072R. Smith - qmcs 200 Today’s Class First hourFirst hour –Questions on homework –Using WYSIWYG web page editors –Recap the hardware hierarchy –Hard Drives –Printers Second hourSecond hour –MS Access Introduction

January 20073R. Smith - qmcs 200 WYSIWYG Web Page Editing Remember the ‘files’ making up a web pageRemember the ‘files’ making up a web page –The HTML file, plus any image files (JPG, GIF) the page needs –Put them in the correct folder – easiest to put in same folder Example Web Page EditorsExample Web Page Editors –Microsoft Front Page – on all campus machines –Adobe Dreamweaver – has been popular in QMCS –NVu – free, open source package Creating the web pageCreating the web page –Like MSWord produces a ‘doc’ file, this creates ‘htm’ files –Unlike MSWord, you must handle the image files separately –Lets you omit all tags from your typing

January 20074R. Smith - qmcs 200 System Unit HierarchyHierarchy –Power Supply –Drive Bays Hard DrivesHard Drives DVD/CD drivesDVD/CD drives DiskettesDiskettes –Motherboard I/O hardwareI/O hardware BIOS ROMBIOS ROM RAMRAM CPUCPU

January 20075R. Smith - qmcs 200 Hard Drives and USBs Hard drives rely on ‘physical’ spinningHard drives rely on ‘physical’ spinning –Magnetics, heads and tracks –Progress = fitting more bits on less magnetic surface USBs are integrated circuits that ‘remember’ their contents after power is turned offUSBs are integrated circuits that ‘remember’ their contents after power is turned off –Various bits of magic used to retain electrical charges –Old (expensive) RAMs magnetized bits of iron and read back which were magnetized

January 20076R. Smith - qmcs 200 Flash Memories: “USB Drives” Flash is ‘electrically erasable ROM’Flash is ‘electrically erasable ROM’ –When you read, you retrieve a value trapped between two transistors Writing requires erasingWriting requires erasing A special high charge erases the previous valueA special high charge erases the previous value A new value is writtenA new value is written Bottom line: USBs get worn out if you write to them a lotBottom line: USBs get worn out if you write to them a lot –Good for music playback, “data archive” –I use mine to move data between home and work “Sync” the files with special software at each end“Sync” the files with special software at each end

January 20077R. Smith - qmcs 200 Hard Drives in Practice Highest storage density of any technologyHighest storage density of any technology –Vendors are good at fitting more bits on a magnetic surface Mechanical requirements keep the costs upMechanical requirements keep the costs up –2 motors, finely engineered disk, shock protection, etc. ImplementationImplementation –Tracks and cylinders –Sectors FormattingFormatting –“Low level” to write sectors to the disk –“High level” to support files and folders (ditto with USB)

January 20078R. Smith - qmcs 200 Printers Common printers todayCommon printers today –Ink jet – popular for graphics Squirts ink onto the pageSquirts ink onto the page Squirting technology and ink establish the applicationSquirting technology and ink establish the application –Laser printing – workhorse printing Xerox/photocopy technologyXerox/photocopy technology Heat the paper surface, attach heat sensitive inkHeat the paper surface, attach heat sensitive ink “Toner cartridges”“Toner cartridges” OthersOthers –Impact – pretty much obsolete except for special applications –Plotters – for huge things; most are now inkjet –3D – believe it or not

January 20079R. Smith - qmcs 200 MS Access Elements of the databaseElements of the database –Inputs –Storage –Outputs SpecificallySpecifically –Forms for input –Import for input –Tables for storage –Queries for output –Reports for output –Export for output