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Feature Presentation for the November general meeting
Bill Marchant - Some Errors Suffered by Computers
General Information
A word of thanks to guest speakers
Newsletter Information
Meeting Schedule for the year
Our November meeting there will be a short
talk on Windows by Bill Marchant and Q&A session by Rob
MacCara. These are the introductory topics. The main topic will
be on "goodies " for the PC user under about 100.00 by
a local retailer. This has been an annual feature and creates
considerable interest in what is available for that "special"
Christmas gift for computer friend. Drop by and enjoy.
The HAPCC general meeting is on the last Sunday of each month.
Please note changer from forth to last Sunday of each month. The
next general meeting will be Nov 28th meeting time 7:00 - 9:00 pm.
For this month we have official approval to use the classroom
facilities at CFB Halifax (Stad) for our regular meetings. New
Place! Building S-37 room B18.
Go in the main gates of Stad on Gottigen street and either
stop and ask the fellow in the gate house for directions or:
Proceed straight through the gates and down the little hill and
keep going straight till you come to a stop sign. Go past the
stop sign and down the little hill and turn right at the bottom
of the hill. The long building facing the soccer field is
Numbered S-37 and the sign out front says that it is the home of
the Naval Engineering School. You've reached the right place.
Find a parking spot and go in the far set of doors (South doors)
- Go Straight in the building and down the stairs to the next
level and turn right. The classroom we'll be using is B18 and it's
right next to the stairwell. The new facilities boasts a room
with 25 computers as well as a projection system that we can use.
See you all there at the next meeting!
In this issue
Decaying radioactive elements emit three kinds of particles:
· Alpha; slow moving, heavy, but stopped by a sheet of paper.
· Beta; smaller than Alpha, stopped by a centimeter of aluminum.
· Gamma; to stop these, a metre of concrete is required.
In 1976, memory chips needed fewer than 1 million electrons to
store the electrical charge that represented the difference
between a 1 and a 0; yet a single Alpha particle could rearrange
up to 1.5 million electrons.
In that year, a research worker for Intel was asked to investigate random bit errors in some of
their memory chips. He discovered that the chips which were
chiefly involved had covers which contained mildly radioactive
substances. Those chips using different covers were not affected.
Intel solved the problem by using radioactive free covers for
their memory chips, and they did so for about a year before any
of their rivals found out their secret.
In a recent article in Scientific American Magazine, there is a discussion of the
probability of errors occurring on hard disks, CD-ROMs and
computer memory. These risks are low. Some examples:
· Hard disks; 1 bit per 10 trillion up to 1 bit per 100 trillion per read.
· CD-ROM; 1 bit per trillion.
· On a 25 Gbyte disk, one could expect 1 undetected error per 50 reads of the entire disk.
· On a 750 Gbyte disk, (which some of us may be using in as little as five years) you would not be able
to read or write the entire disk without an error.
· The T1 Internet line has a specific error rate of 1 bit per million. That is three errors every two
seconds on a single link.
To counter the affects of errors, things like check sums are used. The T1 check sum allows only 1 out of 65,536
corrupted packets to pass unnoticed.
Another technique is error detecting and correcting codes. The use of the parity bit which
was common in earlier computer memories is an example of this.
The use of RAID (Redundant Array of I.... Disks) is another
example. In the case of some versions of RAID, hard disk errors
can also be corrected.
I have mentioned Alpha Beta and Gamma particles, but Cosmic rays, which are all about us are none
of the above. (There are 8 pages of data on Cosmic rays in my
1968 edition of the Encyclopedia Britannica.) Cosmic rays
passing through a computer will cause 1 error every 15 years in
16 Mbytes of RAM. There will be 1 error in 2 years with 128
Mbytes of RAM. Since Cosmic rays will pass through anything
including the earth, shielding would seem to be rather futile,
although it is known that there is a higher density of them at
higher altitudes. A computer in Denver Colorado is several times
as likely to suffer this type of error as one at sea level, and
in high flying aeroplanes the risk is 20 times that at sea level.
The risk is also greater at the equator than at the poles of the
earth, probably due to structure of the earth's magnetic field.
When computers memories reach the sizes which make the frequency of errors unacceptable, there
will be error detecting and correcting hardware built into
computers memories. Who know? Maybe parity bits in memory which
were discarded as unnecessary a few years ago will make a come-back.
In this issue
Chairperson David Potter
Vice-Chair Bill Marchant
Treasurer Rob MacCara
Web Librarian Thayne MacLean
Newsletter Editor Diane Smith
Membership Promotion Pat Conen
and the following members who assist in planning our monthly
meetings: Norman DeForest, Henry Hill, Ken Gilmour,and Colin Stuart.
The HAPCC has two kinds of
meetings. Firstly the regular Sunday night meeting which most
members attend regularly, secondly the monthly (approximately)
planning meeting which organizes the business of the Club,
including what happens on the Sundays. The planning meeting is
held on Monday, a week after the regular meeting in which all
members of the Club are urged to attend. At the planning meeting,
we discuss feature speakers for regular meetings, finances,
membership, training, and other computer related subjects.
....Bill Marchant
A word of thanks to guest speakers and the their web suites.
Our guest speaker at the March meeting was
Mr. David Baxter, Product Specialist at MT&T for the
MpoweredPc service. His multi-media presentation showed us how
far the service has come, and in which direction it is heading.
MpoweredPc was being officially launched on April 7, 1998 and it
promises to be a serious contender in the high-speed
internet/software on demand arena. More info can be found here:
Mpowered
Once again, thank you to MT&T and David Baxter.
Our guest speaker in February, 1998 was Sgt. Bill
Cowper, Internet Communications Officer of the Halifax Regional
Municipality Police Department. He gave a history of how and when
the police department started using the Internet. They were the
first police department in Canada to be on the Internet. Sgt.
Cowper is continually receiving calls from all over the world
looking for assistance. The presentation showed how well the
department and the officers in the patrol cars are versed on
getting the criminals off the streets. If you would like to
check-out their web site the address is:
Halifax
Regional Police Service gives an
idea of what an "Internet Cybercop" is all about.
In this issue
Newsletter Articles.... We are almost
always in need of good articles. If anyone has something that
they feel would make a good article, an interesting story to
tell, or even a good meeting topic, please don't hesitate to pass
it on. Articles can be submitted in almost any format, ASCII
text, AMI Pro, MS Word, Windows Write, WordStar and of course
WordPerfect.
The news letter is mailed to all
paid up members and to anyone who has attended a meeting within
the past three months. Yearly membership dues are $15.00.
Club Mailing Address -
P.O. Box 29008, Halifax N.S., B3L 4T8.
In this issue
We decide the meeting dates for the
upcoming year at the last planning meeting of the season. The
dates for these are listed below. As in previous years, the
December meeting is moved to the early part of January due to
Christmas Eve being near the fourth Sunday of the month.
The planning meetings are normally held on the second Monday (8
days) after the general meeting. They are currently held at a
members home and the address is announced at the meeting prior to
the planning meeting. Anyone is welcome to assist in the planning
of future meetings or events.
Dates for the meetings starting in September are based on the
LAST Sunday in each month. Note that this is a change from
previously, when we met on the fourth Sunday.
November 28, January 9, January 30, February 27, March 26, April 30, May 28, June 25.
Note, there is no meeting in December. Remember also, we are now
using the LAST SUNDAY of the month, except for the exceptions as noted
above.
Any changes to the scheduled dates will be announced where possible at the regular monthly meetings
and/or in this newsletter.
