HlaMin

Category: Computation

  • Digital Equipment Corp

    Digital Equipment Corp

    by Hla Min

    Updated : June 2025

    • DEC was founded by Ken Olson.
    • It produced PDP and VAX.
    • PDP-8 had limitations, but it was affordable to universities and users.
    • UCC bought PDP11/70.
    • Gordon Bell was the architect of VAX.
    • Microsoft bought a part of DEC.
    PDP11/70

    Khin Maung Zaw wrote :

    It’s kind of sad that DEC failed to keep up with their lead beyond PDP.

    I don’t know why Ken Olsen was pushed out, my limited understanding was that he was not high on Unix (he had been attributed to calling Unix a ‘snake oil’), for some reason his attempts to push VAX/VMS didn’t take off as he might have liked. I’ve read it somewhere that he didn’t get much support within DEC on the VAX/VMS endeavor.

    At the time, there was a talented group of DEC engineers in Seattle area (across the lake from Seattle, matter of fact we here called East Side – Bellevue/Redmond). If I recall correctly, the first Microsoft Data Center at Canyon Park, several miles north of Redmond, was ran by DEC folks in the late 80s, early 90s.

    A brilliant OS​ architect, Dave Cutler, part of a triumvirate led DEC’s Star project, a virtual 32-bit extension on PDP 11/70. Star and its cousin Starlet became precursor to VAX/VMS among others. The triumvirate were working at the DECWEST facilities in Bellevue, next to the city of Redmond.

    Around late 1980s, some events – of which I’m no clue whatsoever, Canyon Park Data Center staff as well as many of the DECWEST team became part of Microsoft.

    As the saying goes, “The Rest Is History”. Dave Cutler and his team led the development of Windows NT, New Technology” and beyond. Some folks attributed Billg who manged to extract most of the DEC VAX team into MSFT.

    [A titbit on VAX and NT] Mark Russinovich, received his PhD from Carnegie Mellon in 1994, wrote series of articles in the Windows magazine, comparing the deep down internals of vms and NT. He even discovered the names of the internal variables have the identical names between them.

    He co-founded a company called “Winternals”, developed a set of Windows tools which quickly became a Swiss knife for every Windows engineer. Needless to say, Microsoft bought his company, the tools became part of Windows. Mark became Technical Fellow, and now he is the CTO of Azure.

  • Scam

    Scam

    by Hla Min

    Updated : May 2025

    It is used by dishonest people to cheat unwary folks.

    Nigerian Scam

    • It is one of the oldest scams.
    • Typically, one gets an e-mail supposedly from a friend asking for help (e.g. need money desperately to buy a return ticket home) and to follow instructions (e.g. transfer money) to get him out of the trouble. There is a promise to repay the debt.
    • Some get emotional & forget logic and the importance of verifying (double checking). They rush off to write a check.

    Why Scam?

    • It does not need much effort to scam.
    • Even if a tiny fraction of the recipients fall into a scam, the scammers get rich.
    • Even if they are caught (possibly after a long time), the resources needed to get back the money (extradition, law suit) are too much and not cost-effective.

    Variations

    • Someone claiming that he / she had inherited millions of dollars
    • A company claiming that you had won a big prize
    • Some scenario suggesting “It’s too good to be true”.

    Scammers

    • Some are sloppy copy cats (with typos and errors in the message). If you are careful, you can easily confirm their scams.
    • Some simply change the settings (Edinburgh, Scotland instead of Nigeria). It’s not difficult to confirm such scams.
    • Some may use malware to take over computers and send scams from the hacked account.

    Right actions to beat scams

    • Call your friend and his/her family to verify
    • Use nick names or sensitive information to check if the sender is a hacker
    • Warn friends and families about the attack
  • DSL

    DSL

    by Hla Min

    Updated : May 2025

    Digital Subscriber Line

    • DSL allows a relatively high speed Internet connection over ordinary copper telephone lines.
    • ASDL (Asynchronous DSL) is a variation of DSL.

    Dana Sri Lanka

    • Dana Sri Lanka was co-founded by Sayama Daw Tin Tin Myint (Emma, “May Tin”, “Mae Daw Gyi”, ChE70).
    Emma
    • DSL has provided financial assistance to Burmese monks studying in Sri Lanka.
  • SOA

    SOA

    by Hla Min

    Updated : May 2025

    SOA may stand for

    • Span of attention
    • Service Oriented Architecture

    Span of attention

    Most people have a short span of attention.

    The following are some examples emphasizing SOA.

    • Elevator Speech : Sell oneself to a potential employer/customer during an elevator ride
    • 10 – 30 second Sound Bites
    • A short paragraph
    • One Minute Manager
    • Five Minute Biography

    Architecture

    SOA (Service Oriented Architecture) is a kind of architecture used in Computer Systems and Applications.

  • Confusion & Superstition

    Confusion & Superstition

    by Hla Min

    Updated : May 2025

    • Some people confuse Correlation with Causation.
    • Some people are superstitious and associate Bad Luck with specific signs and events (e.g Solar & Lunar Eclipses).

    Correlation

    • In Probability and Statistics, one has to determine if two variables have positive, negative or zero correlation.
    • Two variables are said to be positively correlated if both go up and down together.
    • Two variations are said to be negatively correlated if one goes up when the other goes down (and vice versa).
    • Two variables are said to be zero (no) correlation, if there is no significant trend.

    Confusion

    • Some confuse Correlation with Causation.
    • Correlated variables may or may not be related as “Cause and Effect”.
    • For example, we hear, “My friend has lung cancer. He does not smoke.”

    Does Smoking cause Lung Cancer?

    The early experiments show some correlation between Heavy Smoking and Lung Cancer.

    There are several parameters in Smoking

    • cigar, cigarette, e-cigarette, cheroot
    • frequency
    • quantity
    • deep inhalation
    • second hand smoke

    Superstition about Eclipse

    • Solar and Lunar Eclipses occur every year. There are Total and Partial Eclipses. We cannot see all eclipses from a place. Some occur in places we cannot see.
    • Some are superstitious. They fear when there are Eclipses.
    • Eclipses are natural phenomena. They do not cause bad events to happen.
    • “A little knowledge is a dangerous thing.”

  • QWERTY Keyboard

    Background

    • Sholes invented the mechanical typewriter. In order to prevent two keys stuck after hitting them rapidly, he designed the QWERTY layout.
    • Business schools and companies trained “touch typing” with the QWERTY keyboards.

    Ergonomics

    • In the English alphabet, e is the most frequently used vowel, and t is the most frequently used consonant. To hit them, a touch typist has to move a left finger.
    • This led to claims that the QWERTY keyboard is not ergonomic; not suitable for efficient typing and It could cause tendonitis and similar medical problems.
    • Computers (desk tops laptops, pads, …) continue to use QWERTY because most people do not want to change their habits, and retraining is costly.
    • Numerous attempts to replace QWERTY were not successful.
    • Many computer users are not touch typists; some use the “hunt and peck” method using two fingers. They do not care about the ergonomics of the keyboard.
    • A few use ergonomic keyboards either with QWERTY layout with two sections (e.g. laid out in V-shape) or with non-QWERTY layout (e.g. Dvorak)

    U Khin Maung Zaw (EC76) wrote :

    In the early days, one of my leads really like Dvorak keyboard and used it on his desktops. One day we had an issue with one of the servers, and needed to logon to it to troubleshoot the root cause. [This was before the advent of the remote access.]

    Even though we had the admin password, no one could logon to it, and the lead was on vacation for couple of weeks. We decided not to rebuild the server as it had some unique applications running on it and the issue was livable, waiting for him to come back. [He was the last person to logon to that server, so we assume he might have changed the password without telling the team.]

    When he came back to work, we told him about the server, naturally he logged on to it to investigate. We asked him what the new password was, he denied he changed it at all.

    Then we discovered he changed the keyboard to Dvorak while using it but did not switch it back.

    The directive was issued across the board not to switch the keyboards on any servers, across all company data centers.

  • Methodology

    Methodology

    by Hla Min

    Updated : May 2025

    Top Down

    • Approach starts with the Design Requirements and then decide on the intermediate and final steps to get the design implemented.
    • Used some software projects.
    • May also be used in the writing of a book. One first decides on the structure and contents.

    Bottom Up

    • Used when one has a set of bases, foundations and libraries.
    • Building blocks are then assembled and refined to develop a desired product.
    • May also be used in the writing of a book. If one has written posts for a long time, they may be used as a basis for further development into an e-book or printed book.

    Middle Out

    • Approach is used to develop several software.
    • Uses a hybrid (part Top Down and part Bottom Up). It is important to make sure that the two parts meet properly.
    • In the context of publishing, a group of writers and editors can come up with a Design for the book, use existing material as much as possible and try to bridge the gap with new material.

  • Number Systems

    Roman System

    Base Numerals and Values

    • I : One
    • V : Five
    • X : Ten
    • L :Fifty
    • C : Hundred
    • D : Five hundred
    • M : Thousand

    Rules

    If a lesser weighted symbol appears to the left of a larger weighted symbol, the lower value is subtracted from the higher value.
    Examples : IV (5 -1 = 4), XC (100 – 10 = 90)

    If a lesser weighted symbol appears to the right of a larger weighted symbol, the lower value to added to the higher value.
    Examples : VII (5 + 1 + 1 = 7), CXX (100 + 10 + 10 = 120)

    Drawbacks

    Difficult to perform arithmetic operations.

    Not easy to read large Roman numbers. Movie companies supposedly use Roman numbers in their copyright dates so that the audience could not quickly figure out if a movie is too old.

    Hindu-Arabic System

    Digits

    In the Decimal system, there are ten digits 1, 2, 3, 4, 5, 6, 7, 8, 9 and most importantly 0 (Zero).

    “The Dawn of Nothing” emphasizes the introduction of Zero thereby allowing the positional system of representing numbers.

    Advantages

    It has several advantages over the Roman Number System.

    • Compact representation
    • Ease of performing arithmetic operations.

    Number systems in Mathematics

    • Integers
      Positive, Zero, Negative
    • Real Numbers
      Positive, Zero, Negative
    • Complex Numbers
      Real Part and Imaginary Part
    • …

    Bases and Usage

    • Base 10 : Decimal
      Most common
    • Base 2 : Binary
      Used in computers
    • Base 3 : Ternary
    • Base 4
    • Base 8 : Octal
    • Base 16 : Hexadecimal
    • Base 60
      Angular and Time Measure
      Minutes & Seconds
    • Mixed Base
      Old British Measures
      e.g. Mile, Furlong, Yard, Foot, Inch

  • Score

    • Soccer
      Early days : Win (2 Marks), Draw / Tie (1 Mark), Loss (0 Mark)
      Later days : Win (3 Marks), Draw / Tie (1 Mark), Loss (0 Mark)
    • Chess
      Win (1 Point), Draw (0.5 point), Loss (0 Point)
    • Examination
      Marks or Grades
      Credit or Distinction
    • Perfect score
      In examination : e.g. 100 out of 100 marks
      In Gymnastics and Diving : e.g. 10 out of 10
    • Value of Twenty
      e.g. “Four scores and seven years ago” (Gettysburg Address by Abraham Lincoln)
    • Music
      Sheet / Composition

  • Seven

    Numeral

    • Hindu-Arabic numeral : 7
    • Roman numeral : VII

    Factors of Enlightenment

    • Mindfulness
    • Investigation of dhammas
    • Effort (or energy)
    • Zest
    • Tranquility
    • Concentration
    • Equanimity

    Days of week

    • Sunday
    • Monday
    • Tuesday
    • Wednesday
    • Thursday
    • Friday
    • Saturday

    Astronauts for Mercury Project

    • Alan Shepard
    • Virgil “Gus” Grissom
    • John Glen
    • Walter Schirra
    • Scott Carpenter
    • Gordon Cooper
    • Deke Slayton

    Colors of the rainbow

    Rainbow over Inlay
    • Red
    • Orange
    • Yellow
    • Green
    • Blue
    • Indigo
    • Violet

    Miscellaneous

    • Heptagon
      seven sided polygon
    • September
      7th month of the old Roman Calendar
    • July
      7th month of the Gregorian Calendar