CS2: Brown

file server

is a computer that returns files requested by users on other computers. (When you request a file from the Brown computer system, you are communicating with a file server.)

Nigerian Letters

Also known as "Advance Fee Fraud" Been successfully run since the 1980's over mail and over the Internet Convinces the target that they will get a huge commission for helping free up money held in an offshore bank account. Target is solicitied for small "fees" and their personal info to expedite the process Of course, no money is forthcoming

Vector Graphics

Alternative scheme for representing images. Treat the image as a collection of graphic objects such as lines, curves, and figures Best rendered on special vector graphics machines Resolution independent and highly scalable More easily edited and often more compact in storage Must often be converted to bitmapped images for display on bitmapped systems such as a PC

Input/Output (I/O) Drivers

An I/O driver is a special program that knows how to communicate with a peripheral device and the CPU To read or write a file to a disk the file manager determines the name and location of the file, and control is passed to the disk's I/O driver, which will send commands to the disk arm, read head, etc.

World Wide Web

An assortment of computers (web servers) connected by the Internet employs a common protocol (standard) HTTP (hyperText transfer protocol), basically "Text on Drugs" Sending and receiving hypermedia documents Hypermedia pioneered at Brown!

Weak vs Strong Authentication

An example of "weak" authentication is: - Username and 4 character pin Stronger authentication would be: - Username and 8 character alphanumeric password with no repeating characters Even Stronger authentication would be: - Username + - 16 character alphanumeric pw with no repeating characters + - Biometric signature and/or a Digital Certificate

Search engines

An internet search engine (like Yahoo or Google) is a program that tries to provide a user with a list of potentially relevant web sites based upon (typically) a few key words provided by the user. The actual "search" is being done by a server (in this case a computer belonging to the search engine company).

"server"

is simply a computer that acts as a utility for other computers. A web server is a server that serves up web pages.

Advantages of Bitmap Graphics

It is easier to create hardware to go from a bitmap representation to the actual display on the monitor (which is why monitors use bitmaps) It is easier to draw pictures of things with imprecise boundaries, (or that consist of so many parts it would not be feasible to draw them all) Your PC utilizes Bitmap Graphics to display everything that appears on your screen Ability to create multiple layers which can be overlayed to create composites

Input Peripherals

keyboards mouse(s) scanners digital cameras and imagers microphones and sound digitizers Video digitizers Sensors (temp, pressure, humidity, vibration, speed, chemical, etc, etc,) Switches Secondary Storage Devices Network Connections (Modems)

Radio Shack TRS-80

The first plug and play personal computer available at retail Programmed in BASIC Very successful Very affordable Limited commercial software Created a cottage industry

Central Processing Unit

manages the instruction-execution cycle FETCH - DECODE - EXECUTE coordinates the activities of other devices

Compiler

program than turns a high-level language program into a machine-language program. (Then when one wants, once can execute the machine-language version.)

Interpreter

program that executes the high-level program directly and translates it into machine language on the fly.

CrytoLocker

program that infected over half a million systems from September 2013 through May, earning its perpetrators an estimated $3 Million

Cyber Attacker Profile

Type of attackers: -Hacker, cracker, infowarrior, vandals -Insiders (majority of attacks) -Organized crime, terrorists -State Sponsored Cyber Terrorists Attacker's motivations: -Publicity / challenge -Financial gain and Fraud -Thrill -Revenge -Political Inst

RansomWare

Type of malware which restricts access to the computer system that it infects, and demands a ransom paid to the creator(s) of the malware in order for the restriction to be removed.

What is the internet?

a loose confederation of data communication networks "data communications": sending digital information from computer to computer "information highway" connecting far corners of the world an open, distributed system: no central control

Bitmap

a method of representing and storing digital images and graphics whereby the image is composed of a collection of individual pixels

Pixel

a spatial sample of a digital image. A pixel element is the basic component of a digitized image, which contains a set of numbers representing the features (color, intensity) of that spatial sample (a pixel may only have ONE color and intensity, therefore it is the lowest element of an image)

Stuxnet

a virus that is widely believed to have been developed by the U.S. and Israeil intelligence communities. It's purpose was to infiltrate programmable control systems used in the process control industries. In particular, this worm was targeted at the controllers that operate the centrifuges used in Iran to process uranium, a key component in the quest for nuclear weapons, or reactors.

Execution Monitor

responsible for ensuring that an error caused by a program does not cause the entire system to crash.

IMB System/360

family of computer systems with backward compatibility established the standard for mainframes for a decade

CryptoWall

infected over 600,000 computer systems in the past six months and held 5 billion files hostage, earning its creators more than $1 million, researchers found

Registers

-Are memory locations that are used to facilitate the movement of data inside a digital computer - Work in conjunction with the system clock which determines the speed with which a computer fetches and executes instructions

Alan Turing

-Broke the code for Enigma machine - Devised the "Turing hypothesis" for AI

Cryptography

-Encryption is the transformation of data into a form that is as close to impossible to read as possible without the appropriate knowledge (key) -Decryption is the reverse of encryption -Encryption and decryption generally require the use of some secret information, referred to as a key

Machly and Eckert

-Headed ENIAC team at Penn - ENIAC (Electronic Numerical Integrator and Computer) - First "general purpose" digital computer

Phishing

-criminally fraudulent process of attempting to acquire sensitive information such as usernames, passwords and credit card details by masquerading as a trustworthy entity in an electronic transaction -an example of social engineering techniques used to fool users and exploits the poor usability of current web security technologies

Operating System

-is a collection of resident programs that -manage the system's resources supervise the execution of processes -provide useful services ex Managing user requests (Supervisor) Interpreting user commands (User Interfaces) I/O control Memory management File management Execution-Monitoring Security Multitasking

1950 advances

1) Freedom from vacuum tubes 2) Allowed the placement of many transistors into a small area

Apple vs. Microsoft lawsuit over Windows

- Apple introduces the first commercial computer using a GUI, in 1983, based on pioneering work done by Xerox - Microsoft was set to introduce Windows 1.0 in 1985 and entered into an agreement with Apple to license and sub-license certain aspects of the GUI interface - In return, Apple was granted use of certain Microsoft products for its computers - 1988, Apple files a $5.5billion lawsuit claiming patent infringement and breach of contract - issue: Apple's contention that Microsoft exceeded the terms of the license and used part of the design that were not included in the license

Ada King

- Daughter of Lord Byron - Wrote "programs" for the Difference Engine, thus making her the first programmer ever

UNIVAC I

- First commercial general purpose computer system - Used to forecast the 1952 presidential election

Altair 8080

- First kit micro computer

Charles Babbage

- First true pioneer of modern computing machines - Designed two prototype calculating machines neither of which was practical to build - Difference Engine - Analytical Engine

Trojans

- Modeled after the ancient technique of hiding a threat inside of a seemingly benign package - are usually attached to emails and contain a program that performs nasty stuff on your computer - When the user opens the email, the system resets and when it boots up, the _____ program does its thing very secretly - can also allow someone to effectively hijack your computer and use it control everything that your machine does without you knowing it (Zombies!)

Worms

- Responsible for today's most widespread attacks and sometimes confused with Viruses - are designed to self replicate and automatically spread themselves from system to system using the network connections - usually use email as their carrier method since email is such a popular application - mail themselves to everyone listed in your address book as an efficient replication mechanism - Anna-Kournikova.jpg.vbs

Difference Engine

- Special purpose calculating machine - Automated both the computation of tables and their printing - Employed the method of differences to calculate polynomials

Magnetic Tape-Sequential

- Stores data represented by magnetized particles in linear tracks - Magnetized clusters or domains are aligned to represent binary codes

Low and High Level Languages

- The closer the language is to machine language, the lower the level - In general, high level languages make things easier to develop large complex programs

Pharming

- a hacker's attack aiming to redirect a website's traffic to another, bogus website - conducted either by changing the host's file on a victim's computer or by exploitation of a vulnerability in DNS server software - Antivirus software and spyware removal software cannot protect against pharming

Public Key Ciphers

- algorithm was published by Rivest, Shamir, and Adleman in 1976 and is know as RSA (for their last names) - RSA is still a widely used algorithm which is a testament to its strength and viability - employ an algorithm with two keys -- a public key and a private key - looks up the recipient's public key and uses it to encode a message

Encryption Keys

- are essential information -- usually a large numerical parameter(s) -- needed for encryption and/or decryption algorithms - are used to encode plaintext as encoded ciphertext - used to decode ciphertext and recover the original plaintext - sometimes discovered by brute force methods employing computers to search large potential key combinations

Spoofing

- the act of creating a website, as a hoax, with the intention of misleading readers that the website has been created by a different person or organization. Another meaning for spoof is fake websites. Normally, the website will adopt the design of the target website and sometimes has a similar URL

Computer Viruses

- "a program that can 'infect' other programs by modifying them to include a ... version of itself" is generally accepted as a standard. - Aka....a illicit program hidden inside of a legitimate program that propagates through various computer and network media - Common example: infect Word documents that may then be emailed to other systems

Word

A multiple of bytes

ROM (Read Only Memory)

Read Only Memory can only be read from its contents cannot be altered or written over easily This type of memory is used to hold instructions that need to always be there and always be the same

Higher Resolution

Renders an image with greater accuracy for any given size

Patents

Reserved for protecting unique innovations and inventions that represent a "new" approach to solving a problem or creating a product or process Takes a formal process of searches, filings and disclosures Approximately 18 month process minimum and $5-10K in cost Patents expire after 17 years in most cases

Imagine Resolution

Resolution (Accuracy), Color accuracy

Direct Access

SEEK — controller advances read/write head to proper track LATENCY — waits for proper sector to rotate under head READ/WRITE — disk head scans the sector for read or write

Optical Discs

Compact Disc-Read Only Memory (CD-ROM) archived and published information Relatively high capacity (650 Mbytes) Compact Disc-Recordable (CD-RW recordable readable using CD-ROM technology Digital Versatile Discs (DVD)/DVD-R) Very high capacity, storages (5-15 Gbytes) Multiple Layers, tighter spacing in the same size as CD And then... BLUE RAY (3-10 times the capacity of today's DVDs)

Typical Graphic Applications - Vector graphics

Computer Aided Design Illustration 3-D modeling and rendering Animation 3-D Games and Simulations

Fetch, Decode, Execute Cycle

Computer instructions are stored (as bits) in memory. To run a program, each instruction is: Fetched from memory. Decoded (the computer figures out what it should do based on the number). Then the instruction is executed. The speed at which this cycle occurs is determined by the system clock

Gordon Bell

Father of the Minicomputer, Digital Equipment Corporation Brought computing to small businesses

Jack Kilby

Invents the integrated circuit at TI 1957

Image Resolution

Is directly proportional to number of bits available for storage

IBM PC

(1982) IBM's first PC Signaled a significant shift for the giant manufacturer Established a new standard which is still being built on today Operating system written by Bill Gates & Co. at Microsoft

John Von Neumann

- "Stored program" concept - Designed the IAS (institute for advanced studies)

Apple's Thunderbolt

"The most advanced I/O EVER!" per Apple Supports high resolution video and high performance data transfers through a SINGLE compact port Up to 20 Gb/sec transfer speed! 40 times faster that USB 2 and 4 time faster than USB 3

The Apple II

(1978) The first commercially available Apple Initially sold to Wall St. bankers who wanted the Spread-sheet program called Visicalc which ran on the Apple II Put Apple on the Map

The Osborne 1

(1981) First "portable personal computer"

Claude Shannon

1916-2001 1937: Introduces the concept of binary logic for use in creating digital computing machines 1948: Publishes "A mathematical theory of communication" which sets forth the principals for encoding information so that it might be transmitted electronically "Father of modern information age"

Invention of hearing aid

1953

Invention of pocket radio

1954

Short History of the Internet

1961-69 Research in distributed communications progresses 1969 Arpanet (Advanced Research Projects Network) is commissioned by the DoD with nodes at UCLA, Stanford Research, UCSB and Univ. of Utah...designed as a "best effort" network 1971- 15 nodes operational w/ 23 Systems 1972- Email is introduced 1982- TCP/IP is chosen as the new communications protocol for Arpanet

Nibble

4 bits

Byte

8 bits

TradeMark

A form of copyright which protects your public brand image and associated design of things like Logos and advertising material

ASCII

Agreed upon code in which every character, number, etc. is given a unique bit code (1 byte)

Bits

All data in a digital device is memory stored in electronic devices that are either on or off (binary). Represented as 1 or 0

Analog vs Digital

Analog is continuous while digital is discrete

The Security Pillars

Authentication Authorization Privacy Information Integrity Non Repudiation Availability

New "Law"

Bandwidth (the amount of information one can pump through a connection) doubles every nine months or so

Hex Notation using 4 bit Nibbles

Binary Hex 0000 0 0001 1 0010 2 0011 3 0100 4 0101 5 0110 6 0111 7 1000 8 1001 9 1010 A 1011 B 1100 C 1101 D 1110 E 1111 F

US vs IBM

By the 1960's IBM dominated the computer industry with a >60% market share In January 1969, the government began a sweeping antitrust investigation into IBM's dominance and attempted to break it into smaller companies that would compete against one another During the six most critical years of the trial, from 1975 to 1980, the parties called 974 witnesses and read 104,400 pages of transcripts The 13-year investigation, which required IBM to retain 200 attorneys at one point, fizzled in the early '80s as the computing landscape shifted from mainframes to personal computers. The government abandoned the tainted effort entirely in 1982, as clones of the IBM PC eroded Big Blue's dominance With IBM, the Justice Department was trying to hit a moving target, but the target had moved so much there was no point in shooting anymore--so they dropped the case People who worked for IBM in the '80s and early '90s said the company routinely fell victim to "pricing death strategy"--a reluctance to lower prices below cost, even on products that weren't selling--to avoid what the government would call predatory pricing Viewed today, the Government's case against IBM appears ludicrous to many in retrospect

Caching Servers

Caching servers are located at locations where there is a high degree of activity They maintain copies of the most frequently accessed web pages so that they can be retrieved "locally" instead of having to go over the internet for each access This works for those web pages that don't change very often Most large businesses and institutions have local caching servers Increases performance and conserves bandwidth

Parallel Bus

Contains many signal paths for very fast data transfer Bulkier, expensive cable and connectors Limited distance capability Where used: All of the paths inside the CPU and between the CPU, main memory and video processor are implemented using parallel busses for the very fastest transfer rates. Any plug in cards use parallel busses as well as internal magnetic and optical disk drives. Most of these busses are either 16, 32 or 64 bits wide

How do you protect your IP?

Copyright registration Trademark registration Patents ( for unique invention) Copy protection On-line registration for every new installation Protect the source code! Audits

Resolution (Accuracy)

Determined by pixel size and number of pixels

Domain Name

Domain names are more intuitive names for IP addresses. The name cs.brown.edu is the domain name for the Brown computer science home page.

Integrated Circuit (IC)

Enabled many transistors to be grouped into a single package Lowered cost and decreased space compared to using individual transistors Today exceeding 10 billion transistors in a single package of 4 square inches. Still the building blocks for all modern electronics today

Clock Signal

Ensures that data is sent and received at certain times based on the clock speed

Machine Language

Every computer CPU has its machine language, the set of instructions it knows how to execute. This is the lowest level. A typical instruction might say, get the contents of a memory location and put it in the accumulator (perhaps in preparation for adding it to another number).

Types of Viruses

File Infector Viruses -Some of the oldest types -Looks like an executable file (.exe, .com, .bin, .sys) -Hides in system memory and embeds itself in applications that the user opens -Capable of infecting multiple application files -Some Infector viruses make a copy of the real application and hide themselves inside the copy. When the user clicks on the file name, the copy runs, not the original. Macro Viruses -Hide in the popular macro commands that are popular in windows applications -These viruses infect any documents that the application opens (Word, Excel, Access, etc.) Boot Sector Viruses -These viruses infect the boot track of the disk drive when the machine is booted up -By altering the boot drive, the virus can render the machine inoperable Michelangelo was a famous boot sector virus that launches on computers on March 6th and puts the infected machines out of service -On March 6, 1992 there was almost hysteria about the effect that this virus would have on all the PCs installed worldwide

File Management

Files are collections of data arranged in a specified format for use by programs Files can reside in memory as well as in peripheral devices such as disk drives, CD-ROMs or tape drives Every file has a name and attributes that specify its size, its location and its type Creating and maintaining references to a system's files is the responsibility of the file manager. The actual address of a file is a pathname, which is made up of the folders in which the file is located (sometimes called directories) and the file name.

Abacus

First developed in Babylonia over 5,000 years ago. Earliest computing devices designed to aid numeric computation

Grace Hopper

First real "computer scientist" Invested the first compiler

Levels of Intensity

For a black and white (Grayscale) picture we might use, say, 8 bits (one byte) to represent 256 levels of intensity, from 0 (black) to 255 (white) For a color picture we would have 3 bytes, one each for the intensity of red, green, and blue respectively (0,0,0) would still be black, while (255,0,0) would be red, (255,255,255) is white, etc. This is commonly called RGB (Red, Green, Blue) RGB typically uses 3 bytes (24 bits) for each pixel so that equates to 16,777,216 different possible colors

DRAM (Dynamic RAM)

RAM allows for both reading and writing in memory. Contrast this with ROM (read-only memory). Most RAM is volatile, or "dynamic". When you turn off the power, the contents of RAM is lost. Sometimes one talks about DRAM which is short for dynamic RAM).

Cycle Times

Generally the faster your computer can get through a fetch-decode-execute cycle, the faster it will perform. Cycle times are measured in "gigahertz", a billion cycles per second. PCs these days reach 3500 Megahertz or 3.5 Gigahertz (3 billion cycles/sec)

US vs Microsoft

In 1998 the Federal govt. filed a massive lawsuit against Microsoft which charged that it was in violation of anti-trust laws by having engaged in: -Predatory conduct (by giving away Internet Explorer for free is exercising unfair advantage over Netscape, which sells its browser) -Bundling (started closely linking Windows to Internet explorer, significant advantage over rivals as a result) -Exclusionary Contracts As relates to the deployment of Microsoft Internet Explorer at the expense of Netscape, a competing product

Apple vs. Samsung

In 2011 Apple alleged that Samsung used some of its IP in its Galaxy III cell phone Apple was simultaneously suing Motorola for similar patent infringement Known as the Mobile Patent Wars aimed at the incredible success of Android in the market, owned by Google Apple's actions against Samsung eventually spread to 50 different lawsuits across more than a dozen countries Samsung and Google countersued Apple in almost all cases In August 2012 a U.S. Court held for Apple and assessed $1B in damages against Samsung Although this judgment is being appealed by Samsung, Apple requested that Samsung be forced to stop selling its Galaxy Android based phones in the U.S. while the appeals are pending. Largest single damages award in recent history.

Transistor Functionality

In various circuits Transistors can be made to: Amplify or Attenuate electrical signals Invert electrical signals Store electrical voltage values Switch electrical signals off and on Transistors can be combined to create logic circuits commonly known as "GATES" Gates are packed into Integrated Circuits commonly known as "Chips"

Serial Bus

Limited paths Lower cost, lower size, lower weight Longer distance (generally) Where used: Serial busses are primarily used to connect external devices and peripherals. The data transfer rates of peripherals connected via serial are generally slower than those connected by parallel. Serial is convenient, relatively inexpensive and getting faster all of the time. The current serial standard for peripherals is called USB 2.0 and USB 3.0

Assembly language

Machine language slightly easier

XEROX

Many of the innovations that became part of the Personal Computer scene were actually invented at XEROX Parc (Palo Alto Research Center) Xerox was never able to successfully exploit those innovations that included the mouse, graphic user interface and the concept of WYSIWYG, (What you see is what you get)

TCP

Messages are broken up into units of a fixed size and sent out on the internet. These messages may be received in an order different from that in which they were sent. Each packet contains a destination address Individual packets may also be lost. TCP may request packets to be resent, and finally it puts the units back in order.

Desktop and Portable Computers (1975)

Microprocessors all-in-one designs, performance/price tradeoffs aimed at mass audiences personal computers workstations

Types of Access

RANDOM ACCESS (Main Memory, Flash) items are independently addressed access time is constant DIRECT ACCESS (Disc Drives) items are independently addressed in regions access time is variable—though not significantly SEQUENTIAL ACCESS (Tape Systems) items are organized in sequence (linearly) access time is significantly variable

Flash Memory

Non Volatile Memory Small, Convenient and Reliable Random Access Relatively expensive in terms of cost/Mb compared to Dynamic RAM Not as fast as Dynamic Ram Prices dropping every day, capacity increasing!

Typical Graphic Applications - bit-mapped graphics

Painting programs Image processing Text displays

Color accuracy

Proportional to memory as is brightness and contrast since their values must also be stored for each pixel

Copyrights

Protects the arrangement of your design including the text, the graphics, the industrial design

User Interface

Text-based Command Line Interpreters (CLIs) terse, powerful steeper learning curves, unforgiving Graphical User Interfaces (GUIs) intuitive, user-friendly slower, less efficient

IP

The Internet Protocol governs addressing and routing. An IP address is 4 numbers, each less than 256. For example, 156.222.111.255 The routers on the web know how to interpret IP addresses and send the packets to the correct destination. IP packets are also known as DATAGRAMS

Packet Errors

The Internet was designed to be a "best effort" network when it was conceived Performance, Security and Reliability enhancements have been band aids on top of the original, simple design Approximately 1-3 % of ALL packets sent over the Internet get lost and have to be re-transmitted

Software

The applications one uses or writes to get stuff done

Resolution

The capacity for detail contained in a message or signal. Representations with high resolution capture more detail than those with low resolution In the case of digital images, resolution is primarily determined by : Number of pixels Size of Pixels Density of Pixels

File Sharing

The legal debate centers on the issue of whether you have the right to share copyrighted material with other parties as opposed to making copies for your own personal use.

RAM (Random Access Memory)

The main computer memory is called RAM (Random Access Memory) It is "random" in that one may access any addressable memory unit independently of any other (and thus in "random" order). In almost all modern machines the smallest single addressable amount of memory is one byte. Memory is measured in megabytes or gigabytes or terabytes

Moore's "Law"

The number of transistors that can be manufactured into a square inch of integrated circuit doubles every 18 months or so. The amount of memory that can be supplied for a given cost doubles every 18 months or so and the speed of computation goes up by a factor of 2 about every 1.5 years

Hardware

The physical components of the computer - central processing unit, memory, input-output devices

Operating system

The program that serves as a buffer between the user and the hardware

How does Google (and similar) work?

The short, short summary is that Google (and other search engines) continuously crawl the web, using a program called a spider or crawler. It stores a local copy of the pages it finds, and builds a lexicon of common words. For each word, it creates a list of pages that contain that word. A query for a given word returns that list, sorted by pagerank. Pagerank is computed based on the pageranks of the pages linking to a document.

Intel 4004 Microprocessor

This technology made the personal computer possible

Origins of the "web"

Tim Berners-Lee and CERN project (1989) Initially a distributed, hypertext system for disseminating physics and scientific research Pages based on a markup language that can be shared by different computer systems

Bitmap Graphics

To display things on the computer monitor, a modern-day computer has built in hardware (memory) for storing a "bitmap" that represents the "picture" that should be displayed on the monitor. The Bitmap is stored in MEMORY.....the more bits stored, the more memory required....

Output Peripherals

Video output displays Color LCD predominately Printers character, line, and page(laser) Audio output Secondary Storage Devices Network Connections

Memory Manager

When we click on a Word document, the OS must bring first the Word program into RAM, and then the particular document we wish to work on. Allocating segments of RAM to each program is the responsibility of the memory manager.

Multitasking

While most modern computers can only execute one operation at a time, it is often useful to give users the illusion that several things are going on at the same time

Wireless

Wifi and Bluetooth