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A short note on the Veterans Memorial Building, An item in
the Canadian Armed Forces in house publication , the 'Warrior' ,
The VMB will be renamed The Camp Hill Veterans' Memorial Building.
The Camp Hill name is part of a tradition dating back to 1758. Here is a link to:
Canada's Veteran's affairs web suite
where one can browse information related to Canada's fallen. and links to other
sites related to Canada's military traditions.
In an other item in the press the Queen has entered cyberspace and the
link isThe British Monarchy-The Official web Site. It is worth
checking out.
The Bluenose, a fishing schooner, is an icon of down east history.
Find the story at Bluenose II Home Port Page
The next general meeting will be May 25th at 6.30 at the Camp Hill Veterans Memorial Building on Jubilee Rd.
Beginners' corner will be done by Rob MacCara, who will talk about computer memory. He will
review the various kinds available, and how we can make sensible choices about it.
The main event will be a presentation by Kirk Sherwood of the North American Missing Children Association
also called NAMCA. He will talk about how NAMCA uses computers to trace missing children.
He will be doing a live demonstration on the internet. For more information
Child Find
The June Planning Meeting on June 2 will be the Annual General Business meeting of the Society. A good turn out is expected in order that the future of the Society can be adequately discussed and planned. Don't forget. 7:30 PM at the Veteran's Memorial Hospital on Monday June 2.
The HAPCS has two kinds of meetings. There is the regular Sunday night
meeting which most members attend regularly, and there is the monthly (approximately)
Planning meeting which organizes the business of the Society, including what happens
on the Sundays. The planning meeting is held on Monday , a week after the regular
meeting in Room 1602 of the Camp Hill Veteran's Memorial Building on Jubilee Road.
(the same building as the regular meetings; different room). All members of the
Society are urged to attend.
At the planning meetings, we discuss feature speakers for regular meetings, finances,
membership, training, and other computer related subjects.
....Bill Marchant
Articles can be submitted in almost any format, ASCII text, AMI Pro, MS Word, Windows Write, WordStar and of course WordPerfect.
Announcements
Overheard on the Internet
File Allocation Table
The Newsletter, a few notes about what goes into this document
Meeting schedule for the upcoming year
This document 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.
Society Mailing Address -
P.O. Box 29008, Halifax N.S., B3L 4T8
Executive:
Chairperson - David Potter
Vice-Chair - Bill Marchant
Secretary/Newsletter Editor - Colin Stuart
Disk Librarian - Thayne MacLean
and but not least Norman DeForest, Henry Hill, Arthur
Layton, Rob MacCara, Andy Cornwall, George Richards, and Diane Smith.
We have only a few announcements for this month's issue.
Membership Expiry Dates
For those of you who are not already aware, the membership expiry dates are printed in the upper right corner of your newsletter mailing label. If you wish to continue to receive this newsletter and know what interesting meetings are coming up, you either have to renew ($15 per year) or come to the meetings and put your name on the list that is passed around.
DELPHI
The Delphi User's Group meets on the first Tuesday of each month. The meetings are held at the CCL Group building 2669 Dutch Village Road in Halifax, at 7:00PM. For more information call Carey Rolfe at 462-4551 or on e-mail crolfe@fox.nstn.ns.ca. or Dave Hackett at 835-3894
Advertising and Want Ads
We don't charge for small individual want ads like the one above. That is any
Society member or other interested person with some computer related item that
they wish to sell, trade, or give away can contact the editor to place an ad in
the newsletter. We would expect that more commercially oriented advertising
provide the Society with some remuneration for carrying the ad.
An ad will normally only appear once but let me know if you reed it repeated.
Ads can be given to me at meetings or give me a call two weeks to ten days
before the next general meeting(newsletter deadline)
A helicopter was flying around above Seattle when an electrical malfunction disabled all of the
aircraft's electric navigation and communications equipment. Due to clouds and haze, the pilot
could not determine the helicopter's position and course to steer to the airport.
The pilot saw a tall building, flew toward it, circled, drew a handwritten sign, and held it in the
helicopter's window. The sign said "WHERE AM I?" in large letters.
People in the building quickly responded to the aircraft, drew a handwritten sign and held it in a
building window. Their sign said "YOU ARE IN A HELICOPTER".
The pilot smiled, waved looked at his map, determined the course to steer to the Seattle airport,
and landed safely.
After they were on the ground, the co-pilot asked the pilot how the "YOU ARE IN A
HELICOPTER" sign helped determine their position.
The pilot responded "I knew that had to be the MICROSOFT building because they gave me a
technically correct, but completely useless answer."
We are getting fatter! I'm sorry that's not really fair. What we are getting is fatter FATs. The
FAT of course, is the File Allocation Table. It is The organizational method by which the
operating systems (OS): DOS, Windows 3.x and Windows 95 keep track of data and programs
stored on hard disks and floppy disks. Since data or program is just another FILE as far as the
disk is concerned, I will refer only to files. But remember that files can be either data or program.
The File Allocation Table is one of the four things that the FORMAT program puts on a disk
when the disk is being formatted. The other three things are the Boot Sector, the Directory Area
and the Data Storage Area. I will ignore the Boot Sector for now, and talk about the other three
items.
On any disk, the Directory Area can be likened to the table of contents of a book. The Storage
Area to the pages of the book, and the File Allocation Table to the index often found at the back of
a book.
When DOS was being developed, it inherited the disk storage system from the earlier CPM
operating system. Hard disks were not used in micro computers, so that any consideration of
capacity much larger than the then-current floppy disks did not need to be considered, although
there was room for expansion as we shall see. In fact the first IBM PC floppy disks held 160 K
bytes on one side only.
The Storage Area is divided into elements call SECTORS. And each sector holds 512 bytes.
(This sector size for DOS has not changed for Windows.) If you divide 160 K bytes by 512 you
find that there would be 320 sectors of storage area. Each of these sectors was given a number,
and the numbers were kept in the FAT. In addition the FAT has space to keep other information
as we shall see.
Lets step back a bit and look at what happens when a file is written to a disk. First, the OS looks
in the FAT to find an available sector. The number of this starting sector is recorded as part of the
information kept along with the file name and some other data in the Directory Area. When the
first sector is full (512 bytes), another empty sector is found. Usually of course this will be the
next numbered sector, but not always. The number of the second sector is recorded in the FAT
area of the first sector, to provide a link. The number of the third sector is recorded in the FAT
area of the second sector and so on until the file is completely written to the disk. The FAT area of
the last sector used contains a special character called the End of File Mark (EOF). Thus the FAT
keeps a continuous record of the condition of all the sectors on the disk. If all the sectors used are
together, the file is contiguous. If, however the OS had to use sectors which are not together on
the disk, the file is referred to as fragmented.
When a file is deleted, the first letter of the file name is changed to a special symbol. When the
OS is looking for space to store another file, the special symbol tells it that the sectors taken up by
the erased file are available to be reused.
When the OS reads a file from a disk, the reverse process takes place. The file name is found in
the Directory. The number of the first sector is also found. The OS then goes to the FAT to find
each of the sectors of the file, until it reaches the one containing the EOF mark. At which point it
stops. When a file is read, it does not alter in any way the material on the disk, so a file can be
read an infinite number of times until it is erased.
To get back to the number of sectors on a disk; The designers of the system decided that about
4000 sectors would enable 2 M bytes of data to be placed on a disk, and this should be large
enough for any conceivable future development. It turns out that a binary number containing 12
bits will hold the maximum number 4096. Thus a 12 bit FAT was decided upon. As we know,
floppy disks in common use still do not hold more than 2 M bytes, but before the designers had to
worry about floppy disk size, the hard disk appeared. Hard disks brought a whole series of
headaches of their own. Chief among the headaches was how to get more data on a disk using the
12 bit FAT.
Without too much trouble, the FORMAT programs for hard disks began to use sectors in groups,
called clusters. (Present formatting programs call the clusters, Storage Allocation Units).
Clusters consist of 2, 4, 8, 16 or more sectors each. Doing the arithmetic once more, you can work
out that using clusters of 16 sectors, the maximum hard disk storage would be 32 M bytes.
There were solutions provided by some versions of DOS, and by some third party programs. One
solution involved increasing the FAT number size to 16 bits. Sixteen bits permits the maximum
FAT number to be 65,536. Using a 16 bit FAT, and 16 sectors per cluster, the maximum disk
storage increased to 512 M bytes. This was better, but there were still two problems: the first was
that disk capacity continued to grow. Disk with Giga byte capacities are now common. The other
problem is the inefficiency of large cluster siu may have earlier copies of the club newsletter where
I discuss cluster size, but let me summarize again. Whenever a file is stored, storage space is
allocated in units of clusters. If a file is 100 bytes, and cluster size is 16 sectors, then 8092 bytes
of the cluster it is in are not used. In fact, for every file on the disk, the average wasted space will
be one half of whatever cluster size is in use. A hundred files on the disk mentioned above will
waste approximately 409,600 bytes.
By reducing the cluster size, more efficient storage can be arranged. In order to reduce cluster size
on very large disks, the FAT number needed to be increased yet again. Recent versions of
Windows 95 now use a 32 bit FAT number. These systems can have up to 2 billion FAT entries.
So the number of sectors per cluster can now be reduced to manageable proportions. This should
provide some room for future growth without running into the maximum FAT number again.
With very large disks, and a large number of small clusters, the use of the disk itself becomes
inefficient. The time taken simply to find a file becomes significant, and the time to move the
read/write head across the disk also is a factor. There are a number of good organizational reasons
as well as these technical ones for partitioning a physical hard disk into several logical disks. But
that is the subject for another essay.
Windows NT uses a system called NTFS (NT File System). It can use FAT 16 systems, but
Microsoft has not promised that the next version of NT will be able to use FAT 32. OS/2 uses the
HPFS (High Performance File System) which can also use FAT 16. IBM has as yet said nothing
about FAT 32. These two systems were both designed for very large hard disks right from the
beginning, and so are much more efficient in both storage and speed.
Just a couple of final things. The FORMAT program knows the difference between a floppy disk
and a hard disk, and continues to use the 12 bit FAT on floppies. It will use the 16 bit FAT on
your hard drive, unless you have the latest Windows 95. There is no 32 bit FAT update for older
Windows 95, If there was, it would require reformatting your hard drive and maybe other
complications. That is probably more trouble than you or Microsoft is willing to put up with.
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.
It does work, that is how a number of articles in previous
month's editions were received, but if you are sending a file
attachment to your message, it should be UUencoded and not a mime attachment.
Newsletter Production Notes
As usual , for those who may be interested, the newsletter was
formatted this month with WordPerfect for Windows 6.1 running on
either a 386SX-25 or a 486DX-33 (each has 8mb of RAM). Much of
the clipart used is from Novell (formerly WordPerfect) Presentations 3.0.
The original was printed at 600 dots per inch resolution on a HP
Laserjet 4M. If I don't have access to this printer then we
print it on an Okidata 850 at Bits and Bytes on Queen Street in
Dartmouth where they allow the Society to print the originals at no charge.
The main body of the newsletter is set in 10 point Palatino with
the article headings being 14 point bold. The title on the first
page is ITC Zapf Chancery Medium Italic 19.2 and 16 points.
There was about the same number of copies made this month as
compared with the last few months, with about 80 copies produced
of which around just under 50 were mailed out. Any extra copies
from the previous few months issues that I have will be brought
to the next meeting for those who are new to the group or may not
be in regular attendance.
I do have a complete set of all the previous newsletters and if
someone wanted to look through these, let me know and I can bring
them to the next meeting.
We decide on the meeting dates for upcoming year at the last planning meeting. The dates for these are listed below:
May 22
June
As in previous years, the December meeting is moved to the early
part of January due Christmas Eve being the fourth Sunday of the month.
The planning meetings are normally held on the second Monday (8
days) after the general meeting. They are also located at Veterans
Memorial Building. Anyone is welcome to assist in the planning of future
meetings or events.
Any changes to the scheduled dates will be announced where
possible at the regular monthly meetings and/or in this
newsletter.
