Ch 6 Evaluating hardware Moore s Law of transistors inside a CPU will increase so fast that capacity will double every 18 months Gordon Moore cofounder of Intel in 1970 Held true notebooks are more expensive for portability desktops are more reliable powerful having an external SATA or a notebook can add more storage space Express Cards on notebooks can also add more space system evaluation check performance of CPU memory storage video audio etc evaluating the CPU 2 units control unit and arithmetic logic unit Control unit coordinates activities of all other computer components Arithmetic logic u performs all arithmetic calculations and makes decisions Intel Core i7 is most advanced desktop CPU ever made by Intel for every CPU instruction CPU must fetch info from RAM decode it execute the instructions and send the result to RAM Called machine cycle CPUs are differentiated by processing power measured by of cores core complete processing section from a CPU in one physical chip also differentiated by work quickness clock speed and immediate access memory cache memory hyperthreading enables new set of instructions to start before previous set has finished 2 or more processors on one chip Multiple cores cache memory form of RAM more accessible to the CPU Levels of CM determined by chip s proximity to CPU Level 1 block of memory built onto CPU chip for data storage Level 2 on CPU chip but slightly further away More storage Level 3 slower for CPU to reach but larger size memory front side bus FSB connects CPU to system memory Bigger better Meghz benchmarks measurements used to compare CPU perf b t processors different CPUs for notebooks desktops cause different reads like battery percentage of time your CPU is working CPU usage improving CPU is not enough to have perfect comp Also look at RAM speed evaluating RAM volatile storage hard drives nonvolatile time for CPU to get info from RAM is in nanoseconds billionths of seconds RAM appears on memory modules called dual inline memory modules amount of RAM on your computer is physical memory measured in GB memory your operating system uses is kernel memory most computers need at least 2 GB of RAM all have a maximum adding RAM to a computer is pretty inexpensive and easy evaluating the storage subsystem nonvolatile devices hard drive over 2 terabytes largest capacity most storage per dollar Solid state drives SSDs offer faster times same tech as flash drives data transfer rate transfer data to other parts of computer in megabytes s hard drive is composed of several plates called platters alignment dictates a binary digit with magnetized spots hard drive capacity it generally measured in GB sometimes TB older harddrives were Integrated Drive Electronics PATA cables hd mb newer serial advanced technology attachment Serial ATA faster and better SSDs have fastest times if you get 2 small drives combine them with RAID technology to speed Raid 0 data spreads across 2 drives very fast but less secure Raid 1 all data is mirrored if 1 drive dies you re still okay Optical Storage optical drives are disc drives that use laser to store and read data store data as tiny pits that are burned into the disc by a high speed laser some optical media come read only so you can save stuff to them blue ray player will do both cds and dvds as well but not the other way around format was between DVD and DVD Most systems are equipped for both Evaluating the video subsystem video display depends on video card monitor video card expansion card to translate binary data into images on your monitor have their own RAM called video memory Graphic processing units GPU is like a CPU but for 3D graphics and such Many have own RAM video card necessities depend on usage gamer vs average user 1 or 2 video cards is usually sufficient video card also controls of colors displayable bit depth Defines color q Evaluating audio system sound card attaches to motherboard some have 3D sound card which is like surround sound but not surround sound surround sound reproduces sound in 8 channels placed in room upgraded sound cards allow more opportunities for musicians evaluating system reliability buy new one to avoid freezes slow performance Many comps are too slow to ensure system reliability clean out start up folder Clean out unnecessary files Run spyware and advanced removal programs Run disk defragmenter if your system crashes often evaluate RAM and check soft hardware software updates can affect system reliability if nothing helps upgrade OS to latest version or reinstall Computing Alternatives open source software freely distributed You can change and redistribute openoffice org free apps like Microsoft office Writer calc impress base database mysql com develop serious database apps email client alternative thunderbird drawing alternatives draw Sketchup google com for serious graphics seamonkey project org for web page authoring Images GIMP OS Alternatives Linux less viruses portability changeable less hard drive space taken Hardware alternatives build a computer Mac OS X snow leopard DIY case motherboard processor RAM hard drive power supply more Ch 9 Keeping your Data Safe cybercrime any criminal action perpetrated primarily through use of a comp cybercriminals individuals who use comps networks internet to do crime Internet Crime Complaint Center IC3 goes with FBI Nat l White Collar Crime center 2009 336 000 complaints of internet crime Lots of credit card fraud according to a survey by MAAWG 50 of Americans have opened spam virus program that attaches to another program to spread more programs Viruses can destroy data slow programs or even gather sensitive info theft of computing devices is also on the rise Computer threats computer viruses main purpose of a virus is to replicate onto as many files as possible and secondary purpose is to destroy files or do annoying things No new files no new viruses virus process individual writes virus with catchy title Person downloads file his comp is infected Person sends file to other person Other person downloads and infects all those files Everyone on network is at risk types of viruses boot sector viruses replicate onto hard drive s master boot record so it runs w boot up before antivirus programs can load logic bombs virus triggered when certain conditions are met opening a file timebomb virus triggered by passage of date time Michaelangelo blackworm worms attempt to travel between systems through network connections to spread
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