Intro to Information Systems I

Intro to Information Systems I Computer Functions and Hardware ISYS 101 Glenn Booker Lecture #1

Syllabus • This course covers the most important concepts of how computers do stuff and talk to each other • Be sure to attend every class, and come prepared – after this one, the lectures should be a review to help clarify what you’ve read • Don’t forget: http://users.snip.net/~gbooker/ Lecture #1

Who am I? • I have over 15 years of experience in software development, primarily for Department of Defense (DOD) and Federal Aviation Administration (FAA) projects • I tend to ramble, so PLEASE STOP MEif you get lost or have a question Lecture #1

Who are you? • What’s your name? • Where do you work, and what do you do? • Are you comfortable: • With word processing and email? • With surfing the Internet? • With spreadsheets and writing presentations? • Have you published a web site before? Lecture #1

Omnipresent Computers • Computers are everywhere in our society • Cars, airplanes • Appliances • Street signals • Toys, etc. • Computers do exactly what we tell them very quickly – no more, no less Lecture #1

What Do Computers Do? • Computers exist to do four things: • Accept some kind of input • Do some sort of processing on that input • Generate output • And store data • Together, these things constitute the information processing cycle Lecture #1

What Computers Can’t Do • So far, computers can’t have emotion, tell themselves what to do, or be creative • Computers only do what their programs have told them to do – are otherwise stupid • Programs tell the computer what functions to perform, and in what order to do them (an algorithm – kind of like a recipe) Lecture #1

Our Responsibility • Computers have no sense of correct or ethical, so we have to perform that function through the algorithms we write and the quality we build into the software • Particularly important for software which might affect life (safety-critical) and software which runs your business (mission-critical) Lecture #1

Computer Hardware • Essential pieces of computer hardware include: • The system unit (“CPU box”), including the floppy drive and CD-ROM or DVD-ROM • Monitor (output) • Keyboard (input) • Mouse (input) Lecture #1

Computer Hardware • Multimedia hardware includes • Speakers and subwoofer (output) • Microphone (input) • And talk to other computers via • Modem (input or output) • Network connection (input or output) • Outputs can also be to a printer Lecture #1

System Unit • The “system unit” also includes everything else required for normal use of the computer, typically including: • Motherboard, Central Processing Unit (CPU), and Random Access Memory (RAM) • Hard drive(s) • Sound card, network card, and video card Lecture #1

Sizes of Computers • Personal computers are most familiar, but computers can range from chip-sized to massive multi-million dollar beasts • Servers, from workgroup servers to enterprise servers, serve groups of computers, and are otherwise not generally used directly by individuals Lecture #1

Software • … is needed for computers to do anything • It is written in a programming language in the readable form called source code • Source code is “compiled” to create object code • Object code is linked to form executable code – the programs you run are executable Lecture #1

System vs Application Software • System software is needed for the computer to function as a computer • Includes the operating system, which manages memory, writes files, and other basic chores, e.g. Microsoft Windows, Linux, MacOS • Application software is the program used for a particular purpose • Microsoft Word, Lotus Notes, Internet Explorer Lecture #1

The Internet • … is a global network of computers which all speak a common set of languages (the TCP/IP protocols) • Most access the Internet via a service provider (ISP) • Main applications are email and the WWW • Commerce applications are increasing Lecture #1

Bit and Bytes • Bit (b) is a ‘binary digit’, namely 0 or 1 • Data transfer rates, such as across a network, or from a modem, are measured in bits per second • A group of 8 bits is a byte (B) • One byte can describe a single character • Storage is measured in bytes; a page of text might be around 1400 bytes of data • Half of a byte is called a nibble Lecture #1

Big Numbers Abound! • 1 kB = 1 kilobyte = 210 bytes = 1024 bytes • 1 MB = 1 megabyte = 220 bytes = 10242 bytes • 1 GB = 1 gigabyte = 230 bytes = 10243 bytes • 1 TB = 1 terabyte = 240 bytes = 10244 bytes • But many cheat and just use thousand, million, billion, and trillion instead Lecture #1

History of Computing • While some forms of data storage and computation go back centuries (abacus), electronic digital computers only go back to 1946 (ENIAC) • 4800 times faster than hand calculations • Programs were wired manually - later computers stored programs on punched paper cards Lecture #1

History of Computing • Four generations of computers so far • First used vacuum tubes and were programmed in machine language (’50s) • Second used transistors and programming languages (’60s) • Third used integrated circuits and timesharing • Fourth uses microprocessors and graphical interfaces (’80s to now) Lecture #1

Microprocessors • Microprocessors take lots of circuit elements (transistors) and put them all in one very small chip • A CPU is the most familiar microprocessor • Intel 4004 (1975) had 2200 transistors • Intel Pentium 4 (2000) has 42 million transistors, and weighs less than an ounce Lecture #1

Microprocessors • Microprocessors’ activities are controlled by their clock - the faster the clock, the more a processor can get done • Early CPU speeds were in kilohertz (1000’s of cycles per second); now typically well above 500 MHz (megahertz, millions of cycles per second) Lecture #1

Microprocessors • Microprocessors’ speed is also affected by their architecture • CISC (complex instruction set computing) had to get the most from a few big instructions • RISC (reduced instruction set computing) runs smaller instructions much faster • EPIC (Explicitly Parallel Instruction Computing) might improve on RISC Lecture #1

Microprocessors • Microprocessors are limited by their word size – affects operating system choices • 8-bit (Intel 8088), MS-DOS • 16-bit (Intel 286), Windows 3.11, 95/98/ME • 32-bit (Intel 386-Pentium 4, G3, G4), Win NT, Linux • 64-bit (DEC/Compaq Alpha, Intel Itanium), some Windows 2000, Unix’es and Linux Lecture #1

Microprocessors • Dominant microprocessors now are • Intel Pentium III and 4 • Xeon versions for servers • AMD Athlon and Duron • Motorola/IBM G3 and G4 (used in Macintoshes and Unix workstations) • Just released is the Intel Itanium, for servers Lecture #1

History of Programming • Each computer has its own assembly language for manipulating data • Programming languages evolved to make programs easier to write and maintain – independent of the assembly language • Fortran, Basic and Cobol were the earliest • Later, C and Pascal were widely used Lecture #1

History of Programming • There are thousands of programming languages ; the most popular languages today include • C, C++, and Java • Basic • Cobol • And lesser known languages, such as Ada, Perl, Smalltalk, C sharp (C#), etc. Lecture #1

Next Programming Generation? • Programming has evolved little in the last decade or so • Object oriented methods have matured, but haven’t replaced procedural programming • Artificial intelligence is maturing • Distributed systems are becoming more common Lecture #1

Inside the System Unit • Now let’s dive into computer hardware in a little more detail, and then see how it works together • The system unit includes cooling fans and a power supply • Most devices have separate connections for power (separate wires), and data (a flat ribbon) Lecture #1

Motherboard • The heart of the computer is motherboard, which holds the CPU (e.g. Pentium III and 4, Athlon, G3, and G4) and RAM • The CPU is either mounted on a card in a slot, or in a socket with hundreds of pins • The type of slot or socket determines what kind of CPU can be used Lecture #1

Random Access Memory • The CPU uses RAM to run system and application software • RAM is mounted in two to four slots • Each RAM stick typically holds 64 MB to 512 MB of RAM • Many kinds of RAM (PC100, Rambus, DDR, SIMMs, DIMMs, etc.) Lecture #1

Cache Memory • In addition to RAM, a CPU uses temporary storage called cache memory • Usually there are two caches, primary (L1) and secondary (L2) • Caches are very small (e.g. 8 kB L1 and 256 kB L2) • Bigger caches are better Lecture #1

AGP slot CPU socket This edge sticks out of the system unit 5 PCI slots 4 RAM slots Electrical stuff! Typical Modern Motherboard ASUS P4T Lecture #1

Bus Speeds • The CPU communicates with everything else (slots and ports) across a “bus” • The faster the bus, the faster the computer • Typical Pentium, G3, and G4 bus speeds are 66, 100, or 133 MHz • Athlon bus speeds are 200 or 266 MHz • Pentium 4 pretends to have a 400 MHz bus Lecture #1

Motherboard Sizes • There are several families of motherboard sizes (which also drives the case size) • AT (Baby AT, Full AT) for smaller personal computers • ATX (microATX, Full ATX, Server ATX) for most PC’s and workstations • WTX, for servers Lecture #1

Integrated Motherboards • Some motherboards build in functions • Sound • Video • Network connection • SCSI controller • This may save money initially, but reduces future expandability Lecture #1

Motherboard Slots • Motherboards have PCI slots which are typically used for • Network card, Sound card, Modem • SCSI card (for other drives) • Older computers have the video card in a PCI slot • Older PC’s have ISA or EISA slots Lecture #1

Other Motherboard Connections • Older other ports on a motherboard are • Keyboard and mouse ports (PS/2) • Serial (ext. modem) and Parallel (printer) ports • They’re being replaced by • USB (Universal Serial Bus) ports, 12 Mb/s • Fire Wire (IEEE 1394) ports are rare, but faster than USB, 400 Mb/s Lecture #1

Motherboard Summary • So the motherboard choice determines • How big the system unit is (case size) • How much RAM may be installed (by the number and type of RAM slots) • What how many and what kind of cards can be installed (PCI, AGP, ISA, etc.) • What kinds of CPU can be used • And hence what operating systems may be used Lecture #1

Video • The monitor is controlled by a video card, which goes in an AGP slot • Accelerated Graphics Port (AGP) slots are in the original speed, 2x, 4x, and Pro speeds • Video cards have their own kind of RAM and processors to help determine what gets send to the monitor Lecture #1

Storage Devices • “ROM” devices are Read Only Memory – you can only read their data (music CD’s) • CD-R devices can also Write CD’s, but only once (CD “burner”) • CD-RW and DVD-RAM devices can read and write from a disc many times, making them like big floppies Lecture #1

IDE Storage Devices • Most personal computers currently use IDE hard drives, CD, and/or DVD drives • They’re cheap and reasonably fast • Limited to four devices on most computers • The floppy drive doesn’t count against that limit – it’s on its own controller Lecture #1

SCSI Storage Devices • SCSI storage devices are typically faster and much more expensive than IDE equivalents • Up to 7 or 15 SCSI devices can be linked • Larger capacities available, and somewhat more reliable than IDE • Used for servers and workstations Lecture #1

SCSI Storage Devices • SCSI devices have evolved over 20 years from a transfer rate of just over 1 Mb/s (megabit per second) to 320 Mb/s • SCSI types include SCSI-1, -2, and –3, Fast, Wide, and Ultra • SCSI connectors have 25, 50, 68, or 80 pins Lecture #1

IDE and SCSI Speeds • Common peak IDE transfer speeds are 33, 66, and 100 Mb/s • SCSI transfer speeds run 20, 40, 80, 160, and 320 Mb/s Lecture #1

What to Expect on a PC? • Typical amounts of RAM range from 128 to 512 MB, but some can handle 2 GB+ • RAM costs about 25¢ to $1 per MB, depending on its type • Typical hard drives range from 10 to 80 GB • Hard drives cost from about $4 to $8 per GB for IDE drives, $10 to $15 per GB for SCSI Lecture #1

Data Representation • Most computers are digital (1’s and 0’s) • Analog computers exist – they solve problems by replicating equations with electricity • We use base 10 for counting • Computers use base 2 (binary), eight (octal), or 16 (hexadecimal) internally Lecture #1

Characters • The Latin alphabet was initially represented by the ASCII character set (128 letters, numbers, and symbols) using 7 bits of data • IBM also used EBCDIC • Unicode is the new standard for representing any language, using 16 bits per character (65,536 possible symbols) Lecture #1

Storage Volatility • RAM and cache memory are volatile storage – when the computer is shut off, they become empty • Most other storage devices (hard drives, etc.) are non-volatile – when the computer is shut off, they remember what was stored Lecture #1

Non-Volatile Storage Devices • Non-volatile storage devices include • Floppy drives • Hard drives • Removable media drives (Zip, Jaz, optical, etc.) • CD-ROM, CD-R, CD-RW drives • DVD-ROM, DVD-RAM drives • Backup tape drives (DAT, DDS, QIC, DLT) Lecture #1

Sequential vs. Random Access • Most storage devices allow easy access to any random piece of data – hence are random access devices • Most backup tape drives only allow access to one piece of data at a time, and must rewind the tape to see others – sequential • Access times for sequential devices is slow! Lecture #1

Intro to Information Systems I