MSG 159765
x (200.92.95.151) - Sat, 28 Jun 2008 23:17:19 +0100
© 2005 Gutenberg-Museum Mainz
MSG 159778
# cue (200.92.94.231) - Sun, 29 Jun 2008 18:53:44 +0100
$222.2222=(2.2.2,22.22)
MSG 159779
. cue (200.92.95.34) - Sun, 29 Jun 2008 20:56:14 +0100
For example, the country of Chad in West Africa saw its debt increase from US$330 million in 1987 to US$1 billion ten years later. Chad′s debt/GDP ratio rose from 28 percent in 1987 to 55 percent in 1997.)

MSG 159780
, cue (200.92.95.34) - Sun, 29 Jun 2008 20:57:21 +0100
Who does this debt crisis affect the most? The poor, who depend on the government for health and education subsidies, are the worst hit. And the World Bank recently admitted that the world added 200 million poor people to the rolls of poverty by 1998 over the 1.3 billion classified as living below the international poverty line in 1993 (people with an income of less than a dollar a day). Tanzania, half of whose population is illiterate, spends a third of its budget on debt payments and spends four times more on debt than it does primary education. Niger, where life expectancy is only 47 years, spends more on debt payments than it does on health and education combined. Altogether sub-Saharan Africa spends four times as much on debt repayment as she does on healthcare.


MSG 159847
i cue (189.164.55.236) - Tue, 01 Jul 2008 21:57:29 +0100
1738, native name, said to be from mong "brave." Mongolian as a classification for "the Asiatic race" is from 1868; mongoloid is 1899 for the genetic defect causing mental retardation (see Down′s Syndrome), from Mongol + Gk. -oeides "like, resembling." Such people were called Mongolian from 1866.
MSG 159850
i cue (189.164.55.236) - Tue, 01 Jul 2008 22:02:13 +0100
members′=memeber`s like 10=1.0
MSG 159851
i.q. (189.164.55.236) - Tue, 01 Jul 2008 22:04:30 +0100
£155.04
MSG 159854
i cue (189.164.55.236) - Wed, 02 Jul 2008 01:45:29 +0100
5188 a little trophy i got for mr. w


MSG 159855
i cue (189.164.55.236) - Wed, 02 Jul 2008 01:50:42 +0100
32.970.240
MSG 159856
i cue (189.164.55.236) - Wed, 02 Jul 2008 01:52:02 +0100
58
MSG 159880
i cu (189.164.58.181) - Fri, 04 Jul 2008 21:16:06 +0100
Introduction
The essential functions of a brain, whether it be that of a human being or the so-called ′electronic brain′ which is being so widely adopted for corn- (calculating apparatus), in automatic control systems, and for bookkeeping and accountancy installations, are the following:
1. the reception of ′information′;
2. the storage of this information (memorising);
3. ability to recall the stored information when required;
4. the initiation of appropriate action based upon selected items of the stored information, in response to a suitable stimulus;

The main differences between a human brain and an artificial ′electronic′ brain are in the manner in which information is applied, stored, recalled and utilised.

In the human brain, information is received via the senses - sight, hearing, touch, smell and taste. The electronic brain, however, receives information only in the form of electrical impulses, meaningless in themselves, but having specific significance when applied according to a suitable code. This coding, of course, must be performed by an external agency - human, .mechanical or electrical, or by a combination of these. Examples of such agencies are perforated-card systems, light-sensitive devices, and tempera- devices.

The mechanism of information storage in the human brain is not precisely known, but there is good evidence that it is partly, if not entirely, electro- In ′electronic′ brains information is usually stored in the form of different conditions of magnetisation or of electric charge, in a number of ′memory elements′.

The recall of previous impressions or stored information in the case of a human brain may be a simple act of will, or imagination, or the reception of some similar or related impression - for example, a particular scent may recall memories of a pleasant evening spent with a girl who used the same perfume. In the case of an electronic brain, however, the recall of stored information can result only from the application of further coded impulses, again controlled by human agency.

Initiation of action in the case of a human brain may again be an act of will, or it may be semi-automatic -.as when a feeling of burning causes one ,to withdraw one′s hand from a hot tea-pot handle - or it may be entirely automatic, such as the beating of the heart. With electronic brains, however, initiation of action occurs only as a result of a specially applied coded signal. It will thus be clear that the potentialities of the electronic brain are in many respects subject to severe limitations compared with the potentialities of the human brain. In particular, the electronic brain possesses no will power, no imagination, no sentimentality, and no discretionary power. On the other hand, a given code signal will always result in the storage of the same information, or the recall and utilisation of the same selection of the stored material. Furthermore, unless some failure occurs in the electrical system, an electronic brain cannot make mistakes due to incorrect calculation or lack of judgment.

The limitations of the electronic brain stem from the fact that, whereas the human brain deals, in the main, with impressions, sensations, facts and ideas, the electronic brain deals only with numbers - and coded numbers at that.


MSG 159881
i cu (189.164.58.181) - Fri, 04 Jul 2008 21:17:36 +0100
Binary Notation

We have said that an artificial brain can deal only with numbers. Of course the human brain can also deal with numbers, but not exclusively with numbers. Human beings, at least in most civilised countries, use for the purposes of recording and calculation what is known as the decimal system of notation, in which any quantity or number can be represented by an appropriate combination of figures or symbols, of which there are ten kinds - the figures 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9.
Most magnetic memories operate on what is known as the ′binary′ notation which quantities (numbers) are represented by suitable arrangements of symbols of two kinds. only, namely 0 and 1. Not only quantities, but also letters, words or commands can be represented by means of the binary code. It will be shown later(*) that all numbers between 0 and 9 in the decimal notation can be denoted in the binary code by various combinations of 0 and1 distributed over four magnetic elements. Larger quantities, of course, require a larger number. of elements.


MSG 159882
i cu (189.164.58.181) - Fri, 04 Jul 2008 21:18:50 +0100
Principle of the Magnetic Memory

The first step in developing a magnetic memory to operate on the binary scale of notation was to select two magnetic conditions which might represent the symbols 0 and 1. The conditions selected are the direction in which each magnetic element is magnetised. It. is well known that a piece. of so-called magnetic material, that is to say a piece of magnetisable material e.g. iron or the iron compound known as ′ferroxcube′, can be magnetised in either of two opposite directions, as indicated diagrammatically. in Fig. 1.


A piece of magnetisable material when magnetised in the direction shown at A might represent the symbol 0, and when magnetised in the direction shown at B, the symbol 1. It is also well known that a piece of magnetisable material can be magnetised only by applying a magnetising force, technically termed a magnetising field or magnetic field. One way of applying a magnetic field is by surrounding the magnetisable material by a coil or loop wire carrying an electric current. The direction of the magnetisation is determined by the direction of the current, as indicated in Fig. 2. where the direction of the current is indicated by arrows.

Thus, if the current flows in the direction of the arrows (as shown at A), the material will be magnetised in the direction previously selected to represent the symbol 0, and if the current flows in the direction indicated at B, the direction of the magnetisation will he that selected to represent the symbol 1.



However, immediately after the magnetising field is removed by switching off the current, part of the magnetism which has been ′induced′ in the material disappears, and only a portion, known as the ′remanent magnetism′ is retained. With most magnetisable materials the magnetism H remains when the current is switched off is very much less than that existing in the material while the current is flowing. The relationship between the direction and strength of the resultant magnetism (denoted B) and the direction and strength of the magnetising x force (denoted H) is shown in the graphs termed hysteresis loops′, reproduced in Fig. 3. For most magnetic materials this graph is of the form, indicated in Fig. 3a, and it is seen that a magnetising force of +Hp results in



a degree of magnetisation equal to +Bp, but when the magnetising force is removed the remanent magnetism is only +BR. Similarly, a magnetising force -Hp results in a degree of magnetisation -Bp and when the magnetising force is removed the remanent magnetism is only -BR.

Because, in magnetic memories, stored information takes the form of the remanent magnetism in one or other of the two states +BR.and -BR, one of them representing ′0′ and the other representing ′1′, it is important that there should be a very definite difference between these two states. To ensure this, a material is therefore chosen in which the value of BR does not differ greatly from the value of Bp. Such a material is ′ferroxcube 6′, the magnetisation curve of which is of the form indicated in Fig. 3b. In actual practice, and for reasons which will appear later, straight bars of iron and complete loops or coils of wire are not used in magnetic memories. Instead, rings of the iron compound ′ferroxcube 6′ are employed, and in place of loops, straight wires are threaded through these rings.





A 20 mil core and a 30 mil core on the wings of a common housefly.
MSG 159883
i cu (189.164.58.181) - Fri, 04 Jul 2008 21:19:22 +0100
The Rectangular Hysteresis Loop
So far we have discussed, in a very simple way, the principles on which a magnetic memory is based. It is now necessary to consider certain aspects of the subject from a more technical angle, and in particular to explain more fully why the material ′ferroxcube 6′ has been selected for use in the equipment to be described.



Fig4
It has been shown that the direction of the magnetisation of a particular ring element is determined by the direction of the current flowing through the wire on which the ring is threaded (see Fig. 4). It should also be understood that the extent to which a ring is magnetised is proportional to the current flowing through the wire, in other words to the Strength of the magnetising field.

The relationship between the direction and strength of the resultant magnetisation (B). and the direction and strength of the magnetising force(H), for the material ferroxcube 6 is shown once more in the graphs reproduced in Fig. 5a.




Fig 5a
Depending upon what has previously happened by way of applying a magnetising force H, a ring core, when no current is flowing in the wire threaded through it, will, due to the special form of the hysteresis loop, be in one of two magnetic conditions: it will either be - magnetised in the direction we will call ′+′, to an extent +B, or in the direction we will call ′--′ to the extent -B, The condition +B, is used to represent the symbol ′1′, and the condition -B,. to represent the symbol 0. In order to change the magnetic condition of the ring core from +Br to -B, or vice versa, a current corresponding to a magnetising force H must pass through the wire. In actual practice, where a number of wires pass through each ring core, the algebraic sum of the currents in all the wires must be equivalent to a magnetising force H.

For example,. imagine that a particular ring is in the condition +B, representing the symbol 1. If a current equivalent to a field of -H is now passed through the wire (see lowest horizontal block in Fig. 5b), the magnetisation will be reversed., the condition changing to that corresponding to point P on the graph. When the current ceases (H becoming zero) the strength of the magnetisation will fall to the value marked -B, that is to say the ring will be in the condition representing the symbol 0.




Fig5b
Similarly, if the ring core is originally in the condition -B, the application of a current pulse corresponding to a magnetising force of +H will change the magnetisation to the point Q on the graph and, on cessation of the current, the magnetisation. will drop to the value +Br.

Again, because of the rectangular form of the hysteresis loop, the application of a current pulse corresponding. to a magnetising force of 1/2 H in either direction will make no permanent change in the direction of the magnetisation. If the core is in the condition +Br, the application of a magnetising field of 1/2 H will temporarily drive the magnetisation either to the value represented by +R on the graph or to the value represented by -R, and on cessation of the current the magnetisation will return to the value +Br.

Similarly, if the core is in the condition -B, the application of a magnetising field of 1H will temporarily drive the magnetisation either to the value represented by -S or to the value represented by -S1. On cessation of the current the magnetisation will again return to -Br.

Furthermore, the graph shows that if the core is in the condition +B,. and a current pulse corresponding to a field of +H is applied, the magnetism will not change permanently, but will merely rise to the value represented by point Q, returning to the value +B,. when the current ceases. Similarly, if the core is in the condition -B, the application of a field of value -H will merely temporarily increase the magnetisation to a value represented by point P, and on cessation of the current the magnetisation will again become -B,


MSG 159884
i cu (189.164.58.181) - Fri, 04 Jul 2008 21:20:15 +0100
Relation between the Decimal and Binary Codes
It was stated earlier that any of the ten symbols 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 of the decimal notation can he represented in the binary code by different combinations of the conditions 0 and 1 in a group of four elements. This can be simply explained by reference to Fig. 8 which shows the four elements.
Any element in the condition 0 is considered as equivalent to. the decimal symbol 0. An element in condition 1 corresponds to the decimal symbol1,2, 4 or 8 according to its position in the group. In mathematical terms. the elements themselves, reading from right to left in Fig. 8, when in the 1 condition correspond to 2o(=1), 2x10(1) (=2), 2x2(=4) and 2(3) (=8). In the 0 condition any element corresponds to 0, as previously stated. The actual decimal digit represented by a group of four elements is obtained by adding the four decimal symbols which the four elements represent.The table below indicates how any decimal digit (0 to 9) can be expressed in the binary code with four elements (,bits′).




Fig8 - Table of the binary-coded decimal digits
In a magnetic memory, the four elements required to represent a decimal digit are not mounted side by side as-in Fig. 8, but stacked one above another as shown in Fig. 9. Here, reading upward from the lowest element (A) in the stack, elements in the 1 condition will represent 1, 2, 4 add 8. These four elements occupy corresponding positions in four matrix planes. It is important to remember that in order to store decimal numbers in the binary code a memory requires at least four matrix planes.




Fig9
The X- and Y-wires of the stack of four elements are so connected that one X-pulse and one Y-pulse will influence all four elements required to represent a decimal symbol.




Matrix plane being wired.
Threading the wires of a core-mass memory containing some 130,000(30 mil) cores.


MSG 159885
i cu (189.164.58.181) - Fri, 04 Jul 2008 21:20:47 +0100
How Numbers Are Stored in a Memory




Fig10
Fig. 10 represents the bottom left-hand corner of each plane in a stack of four matrix planes, only three core elements being shown for the sake of simplicity. In this diagram, cores which are in the 1 condition are shown in black; cores in the 0 condition in white.

dw &I numbers of n figures


MSG 159886
i cu (189.164.58.181) - Fri, 04 Jul 2008 21:21:47 +0100
How a Binary-Coded Decimal Digit is ′written in′
The process of storing or memorising information, in this case a binarycoded decimal figure, is termed ′writing-in′. It is now necessary to explain in rather more detail how this is carried out. It is done with the aid of three of the four wires which are threaded through



Fig11
the ring cores. These are the Y-wire, the X-wire and the Z-wire. The Y-wire is so arranged that it passes through each core in the stack of four in one direction; the X-wire passes through each core in the stack of four at right angles to the Y-wire, and the Z-wire passes through each core in a particular waffix plane in the same direction as the X-wires (see Fig. 11). We will take as an example, the process of writing in the decimal digit 9 which, as we have already seen, is represented in the binary code by a stack of four cores magnetised in the sequence 1, 0, 0, 1.

Fig. 11 shows diagrammatically the stack of four cores, one on each of four matrix planes, which is to be brought into the conditions 1, 0, 0, 1, together with the X- and Y-wires and the four Z-wires. It should be noted that each Z- wire, one for each matrix plane, is controlled by a separate switching device.

Starting with all four of the cores concerned in the 0 condition, if current pulses equivalent to a magnetising field of +1H are passed simultaneously through the X- and Y-wires, all four cores would change to the 1 condition. But in order to write in the digit 9, it is necessary that the two centre cores shall remain in the ′0′ condition. This is achieved by passing at the same time a current pulse correspo~ to a field of -AH through the, Z- (or ′inhibit′) wires of the two centre planes. This is shown in the diagram by the positions of the Z-switches

It will thus be clear that the top and bottom cores of the stack of four are subjected to a field of +1H by the Y-wire and a field of +1H by the X-wire, making a total of (+1H) + (-4H) = H, and will therefore change to condition 1, while the two centre cores are subjected to a field of +JH by the Y-wire, a field of +1H by the X-wire, and a field of -1H by the Z-wires, making a total of (+1/2H) + (+1H) + (-JH) = +1H only, so that they will not change from their original 0 condition.


MSG 159887
i cu (189.164.58.181) - Fri, 04 Jul 2008 21:23:06 +0100
Matrix Plane



MSG 159888
i cu (189.164.58.181) - Fri, 04 Jul 2008 21:25:25 +0100
helo wall street people
MSG 159889
i cue (189.164.58.181) - Fri, 04 Jul 2008 21:29:15 +0100
why does harvard have the computer credits and not m.i.t.
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