Privacy. Pro or Con?

All networked computers share resources with other users. This makes network security challenging. People such as Richard Stallman say that anything on a networked computer is sharable, which seems quite extreme to me. Most people want the contents of their computers to be private and only sharable, if they so choose. This requires firewalls and restricted access to your personal files.

Some security measures we talked about in our lecture include:

• Strong passwords. Mix upper and lower case, include special characters and don’t include your name, the word “password” or “1234” etc.
• Don’t trust just any downloaded file, it may contain a virus or spyware.
• Watch out for “phishing” sites, that act like a legitimate company, but actually steal your personal information and PIN codes.
• Keep your operating system and browser up-to-date with latest security patches that fix potential security loopholes in the software.

The professor mentioned spam filters, which are pretty good at placing unsolicited email in your junk folder, but you may want to check it once in a while. Sometimes important emails get filed there automatically, by mistake.

Industrial Revolution

This week’s lecture slides talked about the Industrial Revolution. During the past 50 or so years, computers have been used more and more to automate tasks, previously requiring humans. Professor Heap points out that a similar major shift from human to machine occurred during the Industrial Revolution, a major turning point in human history. It was a transition period from about 1760 to 1840, including going from hand production methods to machines, greatly influenced by the increasing use of steam power. This changed our energy sources from bio-fuels, such as wood, to coal. This overlaps my study in another course I have this year, ‘Big Ideas: Energy’. We’ve learned that the first machines using coal were built to extract water from coalmines to get more coal. It began in Britain and within a few decades, spread across Western Europe and the United States. This shifted production methods from ‘prime movers’ such as humans and domesticated animals (oxen, horses etc.) to steam engines, powered by the combustion of coal. It seems we are just changing the way we ‘power’ our endeavours. If it’s human powered the energy comes from food intake. If it’s computer powered, it’s probably electrically powered, which usually comes from a power plant, powered by coal, or some other fossil-fuel.

HTML

This week’s longer lecture notes touches on HTML (Hypertext Markup Language). HTML annotates a document with tags that define the structure of the document. This instructs the browser on how to display the content. For example, it tells the browser the title of the page by wrapping the words in title tags i.e. <title> Title Page </title>. It also tells the browser to bold certain words by adding tags i.e. <b> Bold this </b> . The most important function in my opinion is the ability to hyperlink. This is what you see when a word is usually blue and underlined. Almost everyone who uses the web knows that clicking on this will instantly open another page pertaining to that word. This page could be within the same website or on another site all together, on the other side of the world. HTML is very easy to learn, W3schools has some good tutorials.

Operating Systems

The modern OS (operating systems) we use today have a GUI (Graphical User Interface). This allows users to interact with their computer through graphical icons and a mouse pointer. This is a big difference from prior OS’s like MS-DOS, that used command line prompts.

Who originatated of the modern GUI OS is a touchy subject. Microsoft’s Windows is usually accused of copying Apple’s Mac OS. But, further research shows that Xerox had preceded both and greatly influenced Apple’s Mac OS.

Our lecture mentioned that no matter what OS we use , we expect:

• A kernel that provides a shell, shielded access to hardware, referee sharing etc.
• And system utilities; backup, restore, defragment etc.

We should choose our OS based on our social network, what our friends and colleagues use, and the applications we plan to use.

Data Storage Devices

Many data storage devices have come and gone since the dawn of computers. The overall theme has devices becoming smaller, with a larger and larger memory capacity.

Here is a list in (sort of) chronological order beginning with punch cards  (we could start at using a stone as a landmark):

• Paper card
  • Punched card (mechanical)
• Tape
  • Paper tape (mechanical)
  • Magnetic tape (a tape passing one or more read/write/erase heads)
• Disk
  • Floppy disk, ZIP disk
  • Holographic
  • Optical disc  such as CD, DVD, Blu-ray Disc
  • Minidisc
  • Hard disk drive
• Magnetic bubble memory
• Flash memory /memory card
  • xD-Picture Card
  • MultiMediaCard
  • USB  flash drive
  • SmartMedia
  • CompactFlash
  • Secure Digital
  • Sony Memory Stick
  • Solid-state drive

IBM says it’s possible to store a bit of information on 12  atoms.

Palindromes

Nothing to do with Sarah Palin.

This week we learned a simple racket program to identify palindromes.

; palindrome? : string -> boolean

; Is s a palindrome?

(check-expect (palindrome? “rotor”) true)

(check-expect (palindrome? “brake”) false)

(define (palindrome? s)

  (cond

    [(< (string-length s) 2) true]

    [else

     (and

      (palindrome? (substring s 1 (sub1 (string-length s))))

      (equal? (string-ref s 0) (string-ref s (sub1 (string-length s)))))]))

Welcome to DrRacket, version 5.3.6 [3m].

Language: Intermediate Student with lambda; memory limit: 1024 MB.

Both tests passed!

>

A palindrome is a word or phrase which reads the same in both directions. The word palindrome is from Greek – palíndromos, meaning running back again. A palindrome is a word or phrase which reads the same in both directions. Some examples (www.fun-with-words.com):

RACECAR	DEED	LEVEL	PIP
ROTOR	CIVIC	POP	MADAM
EYE	NUN	RADAR	TOOT

The longest single English word in common usage, which is a palindrome, is REDIVIDER