Digital Computing Machines

3.5 PC PSU types

2006-09-12T11:13:00.000+02:00

All important computer hardware need specific amount of el. energy. This means that computer needs constant, stabile and reliable el. energy source with exact defined voltage and power values. With the development of PC computers, power supply unit also has made bigger or minor design changes. First models PC-XT used XT power supply units with 150-200W. Starting with AT286 computers used AT PSU with 200-250W, until first Pentium 2 computers. Today it is mostrly used ATX (for Pentium 2 and Pentium 3 computers) and ATX-P4 with 300-350W. Voltages that request computer hardware components are mostly standardized:

Comparing to standard ATX PSU ATX-P4 has extra 4-pin connector with +12/6+6A
In addition to standard PSU for PCs are used unstandard versions, mostly for server configurations. Those PSU allow so called tandemic work, meaning working two or more PSU at the same time so reliability of power supply could increase and leave redundancy which is of high importance for network servers. Those PSU are usualy allowed replacement with power on (hot plug). Mostly are montated on industrial boxes, rack.

3.4 Simple example of SWPSU

2006-09-11T12:36:00.000+02:00

SWPSU - Switching Power Supply Unit

Rin has multiply role:
1) reduces current that flows towards MoIL and SB (supervisor block) and by doing them, it protects them of high voltage.
2) Rin with Cin devides voltage which determins potential of R point (Ur)
3) Rin and Cin makes stabilization time constant τ = Rin * Cin by which is stabilized value of Ur voltage.

This is neccesary, because otherwise, devider of voltage with to resistance do point R to much unstabile which would affect adversly to MoILs work.

Capacitor Cin has two time role:
1. It makes voltage devider with Rin
2. With its capacity affection stabilizes Ur voltage

Diode D1 has also two time role:
1. Prevents flew of D.C. through N3 that would be warmed unneccesary, and also N3 without diode would short circuit Cin so Cin would loose its function.
2. D1 rectify current that inducts in N3. That voltage is proporcional to output voltage, so voltages referent points like Ur depends from Ua voltage, which reprezents state of output voltage(PSU weight).
This is very clever solution because MoIL reacts on on changes on network power, network condition, and also to changes to weight on PSU.

Zener diode protects swithcing transistor from high values of induced EMF (elektro-magnetic force), that appears when closing inductive suppliers (primar of transformer, and also collector weight on T1). Most of switching transistors for proffesional purposes have integrated diode into transistor box, so integrity of transistor can't be examined with classic ohm way.

3.3 Working method of MoIL

2006-09-10T20:41:00.000+02:00

MoIL manipulate with times when is T1 open and when is closed. When T1 is opened through its collectors weight (primar of transofrmer) current Ic flows.

T = T1 + T2 = const.
T = 1/f = const.
f = 40 kHz
T = 25 µs

1. T1 = T2 = T/2 (stacionarno stanje)
2. T1 > T2
3. T1 < T2

Case 1:
In some stationated condition with constant weight, T1=T2=T/2. This means that transistor is 50% closed and 50% opened.

Case 2:
If becomes rise of use, consumers will take more Ampers then before. (from 8 to 12). Output voltage +5 V will start to fall and will fall to 4,99 V and supervisor block will detect that and "inform" MoIL about that. MoIL will react with extending time of opened or closed T1. Longer T1 means longer openess of transistor or longer current Ic flew through transformer primar. This means that through primar flews more energy so more energy is transformed to secundar of transformer so it is kompenzated higher use of energy and output voltage is now 5 V.

Case 3:
If begins reduced use of energy and output current instead 10 A falls to 8A that will influence to output voltage that will start to easily grow and it will grow from 5 V to 5,01 V which will detect supervisor block and "inform" MoIL about it.

MoIL reacts with shorting T1 and lenghtenin T2 and thats why transistor is shorter time opened so collector current Ic flews for short time period and reaches minor value. That means less flew of energy through primar and time and through secundar of transformer and less energy comes to output and output voltage is back to 5V.

Reaction of power unit supply is very fast for duty load because everything is done within one period T (25µs) which is enough fast, for even the most sensitive components (RAM) not to notice it.

3.2 Switching power supply unit

2006-09-10T00:01:00.000+02:00

Considering that classic power supply unit has too many weaknesse, for much better solution is used SWPSU(Switching Power Supply Unit). Its work method is far more complicated and requires more elements, but price is lower when it is produced in serial production.

Block sheme of Switching Power Supply Unit

Working principle is relativly simple and it is based on multi conversion of A.C. to D.C. and vice versa. Basic voltage is network voltage 220V/50Hz (somewhere 110V/60Hz depending on network standards in each country). Using gretz this is converted to D.C. and in point A (Ua) on filter capacity C1 we get voltage Ua=350 V D.C. (note again, this is for 220V/50Hz standard for network voltage). This voltage isn't acceptable for computer components which accept much minor voltages like +5.0 D.C. +12 -5 -12 +3,3. Taking down voltage from 350 D.C. to +5.0 V D.C. can be done in different ways. The worst part is to use serial of resistants. The efficiant one is to use transformer but transformerses inputs reques A.C. and input of transformer for D.C. is just a short circuit.

Thats why D.C. is artificialy converted to A.C., by CHOPPER (transistor T1). Frequency of chopping is 40 KHz so primar of transformer gets amplitudes of 350 V. Chopper is high voltage transistor T1 from series BUX(automobiles), BUY, BUZ

Tr. T1 works in active amplifing regime but it gets pretty hot so it needs to be mounted on specific cooler.
2 most warming components are switchig transistor (copper, T1) and tranformer because all energy flows through them. Transformers primar is collectors weight on T1 which is adverse because collector weight is individual and in momend of T1 braking (stoping of el. flow) and stopping of el. flow in transofrmers primar inverted self-produced reversed EMC (electro-magnetic current) is produced which tryes to overpolarize tranformer.

It is usual for transofmers to be dimenzioned for ther power that they transform and to other voltages with which they operate. This primarly worth for network transformers where operating frequency is 50Hz and core is made of so called tranformers sheets. On 40KHz transformers sheets wouldn't be good solution because of big losses, and thats why are for producing of these special transformers is used ferrite. Ferrite presents special mix of iron dust and synthetic rosin. Rosins do isolating every particle of iron dust, so electric admittance of ferrite is very small like at ordinary isolator. Magnetic preferences are very good even if weaker in comparation with transformers sheets. Because of high operating frequency core surface can be much minor unlike network transformers.

3.1 Weaknesses of classic power supplies

2006-09-08T14:22:00.000+02:00

Classic cheme is very familiar but it isn't used in PC power supplies because it has too much weaknesses:

1) It is neccesary to use network transformators, Tr1, which is very expencive and large element and that isn't acceptable for PCs. For power of 200W weight of Tr.1 is aprox: 5 kg

2) Filter capacitor C1 has big numbers of values, in mF wich makes whole thing more expencive

3) Network Tr. has fixed ratio of transofrmation, that means:
Np = Up / Us = 220 V / 5 V = 44
that if network voltage is down from 220 V to 110 V, secundary voltage would fall down from 5 V to 2.5 V. That means that in point Ua from 7.5 V voltage would be 4V. Thats the reason for T1 to stop its work and it would be inverted for a moment. That means this classic PSU (Power Supply Unit) doesn't give very good protection.

4) Transistor T1 is key stability element by which is secured stability of exporting DC (direct current). T1 works in linear amplifying regime which means that his operating temperature is high. Because of high technical disipation transistor requires efficient cooling (Fan + cooler)

5) Classic sheme doesn't give any protection from so called current holdbacks which are present all of the time on network. Classic sheme has protection of overflow and short circuit on output

2.3 Operating Systems

2006-09-07T00:01:00.000+02:00

Structure of OS isn't precisely determined but we'll accept sturcture offered by some of highest authorities from OS theory area (Denis Richi, Per Hansen, Ken Tomson). According to them structure of Operating Systems is as follows:

1. Kernel (core of Operating Systems)
is representing vital part of Operating Systems from which key attributes are depending on: stability, reliability and efficiency. Every mistake on kernel files usualy means crash of Operating Systems and reqest for reinstalling.

2. Drivers
This part of OS ensures support for new pluged in hardware and secures isolation of kernel and application software from connected hardware, which is very impotrant because, development of Operating Systems is made easier.

3. Shall
This part connects every other parts into one union and synhronizes common work. Special part of shell presents user interface which directly affect simplicity and efficiency of using Operating Systems. Today it is usual, so called GUI (Graphic User Interface)

4. User tools and programms (utility)
This part of OS isn't necessary but it can make work confortable. In this group we can put different desktop themes, screen savers, debuggers, word processors and other. Special part of utility enables optimization of OS but is very unstable because it can cause OS crash. This is usualy weakest documented part of OS.

Vital Operating Systems caracteristics
On the market there are relativly big number of Operating Systems made for different categories of users. Every Operating Systems cann't be compared in different ways, but some caracteristics are in real life, more important then others:

Most important caracteristics of Operating Systems are:
1. Stability and reliability - presents average time between crashes of 2 Operating Systems in different conditions. These are extremly important datas because they can produce big financial damages. Server Operating Systems must have much better stability and reliability then Operating Systems made for individuals. Crash of server Operating Systems can led to stopping of funcioning of computer network with hudereds computers and cause big financial damages.

2. Functionality - presents rate of hardware support and support of application software to new hardware and software products. In real life Operating Systems made for individuals users show big rate of functionality and easier accept new hardware and software. Server Operating Systems usualy are much more conversative and accept to work only with products that are in their HCL (Hardware compatibility list) for specific Operating Systems.

3. Efficency presents speed of Operating Systems making its functions. We can talk about eficient Operating Systems which making of system operations is almost optimal (access to mamory, hard drivers, etc..) but there are Operating Systems that aren't efficient as those ones.

4. Simplicity of use presents average time thet is needed for usual user to learn Operating Systems functioning. For example, we can say that windows is relativly easy to use (user friendly), while Unix-like Operating Systems are relativly hard for application, they require more learning time.

Operating Systems, in global we devide to network Operating Systems, and Operating Systems made for individuals. Network OS are those OS which are used in network enviroment, which means that they should be more stabil and reliable.

Most known, newer network Operating Systems are:

- Windows NT (Server; Work Station)
- Windows 2000 (Professional, Server, Advanced Server, Data Centar)
- Windows XP Pro
- Windos 2003 Server
- Unix
- Linux
- Novel NetWare

OS made for individuals can possess limited network ablilities, but that isn't their primary purpose. Most known representations are:

- DOS
- Windows 95/98/98 SE, ME, XP Home Edition

2.2 Enviroments for rapid software development

2006-09-06T22:33:00.002+02:00

These are software packages that have more abilities than other programming languages. In this group we can put VB (Visual Basic and VB .NET), Delphi, Clarion, Cliper.

Clarion is considered as the most powerful one, but is rarely used.
Cliper is considered as the most simple one.

SQL - Structure Query Language
Java, Visual Studio, Oracle Dev. Kit

Developing platforms are very complex software packages which make so called developing enviroment, ambient for developing of applications. Most popular ones are:
- Java (SunMicrosystems)
- VS (Visual Studio - Microsoft)
- Oracle SDK (Oracle)

Java is platform which is made as generator of "transparent" applications. This means that applications developed in Java could work in every operating systems whithout bigger errors. Thats why these applications are primary made for www (internet) because, there are lots of computers with different operating systems and different hardware platform connected to it.

VS (Visual Studio) is Microsoft developing platform which presents union of applications based on some of VB (Visual Basic) versions. Applications made in VS can work only on Microsoft Windows.

Oracle is developing enviroment for managing transaction databases. Transaction databases are very sensitive and complicated systems and mostly used for managing financial flows, money. This means that extreme reliability and security is required. Oracle is system that offeres high reliability and data protection.

2.1 Software

2006-09-05T16:45:00.002+02:00

There are two types of software: system and application. System software is set of programs made for solving global IT issues and developing of application software.

Application software:

Application software is contained from program packages made for solving user problems. Avarage user of computer doesn't have time nor money for developing usable complex applications, like database, spreadsheet, word processor, etc... Thats why big number of users use already developed program packages made for solving specific problem(s). Most popular applcation packages are:

- word processor (Microsoft Word (Office), Corel WordPerfect, OpenOffice.org, etc..)
- spreadsheet (Speedsheet, Microsoft Excel (Office), Quatro pro, Lotus, etc..)
- database (Microsoft Acces, Paradox, Fox Pro, D-Base, Oracle, etc...)
- CAD/CAM (Custom Aided Design / Custom Aided Manufacture) (Auto CAD, Arch CAM, MAT CAD, P-CAD, Or-CAD, Catia)
- Desktop programs(programs for preparing of print) like Corel Draw, Photoshop, etc..

With help of these programs, process of preparing for printing of avarage book is shorten from 2 years to 2 months.

- Top menagment programs (Microsoft Navision) This is special class of software for mission to help menagers of big comanies for making buisness decisions, analytics of buisness.
- Multimedia packages for editing picture, sound, movie, etc... (Pinnacle Studio)

Software platforms and tools for faster development of applications

Software platforms and IDE (Integrated Developing Enviroment)

This is special category of software which by it complexy and possibilities put itself above standard programming languages. Most popular developing platforms are JAVA and ORACLE

JAVA is proprety of company Sun Microsystems and has been developed to serve astool for developing transparent applications, meaning, applications that will be able to run to any platform without changing the code. That is extraordinary proprety that enables non painfull functioning of internet where beside of PC, Machintosh are included, graphic works stations, big servers, and mainframe computers.

ORACLE is developing platform by which is done controling of big databases. These are not clasic databases but also transaction databases. Beside database there is support for protecting those transactions from unauthorized access, and they are mostly used in banking and similiar institutions. Transaction is complicated process which must be done completly, without errors. Otherwise if there is some error transaction must be done again.

Tools for rapid developing

Those are tools that have expanded its functional possibilities unlike standard Programming languages. Thats why generating of user application much faster and mostly less complicated.

Most popular ones are: Visual Basic, Delphi, Clarion and Clipper.

1.5 Programming Languages

2006-09-05T16:45:00.001+02:00

Programming languages

Similar to classic languages, programming languages have their syntax and semantics. Syntax is the way of writing commands, and it is checked by compiler.

Checking is done for:
- are appropriate symbols were used
- are appropriate instructions were used
- are format of datas ok
- is program executable in appropriate time (is there any undefined operations,
dividing with zero)

Semantics is quality higher level and includes checking of logistics of program that satisfied rules of syntax. That means that it is needed for results of editing to be correct result otherwise the program would have no sense. Expressions: V=a*b*c and V=a+b+c are correct in syntax way, and computer can calculate those 2 expressions but V=a+b+c wrong and if we want to calculate Volume of body with given dimensions a,b and c.

Programming languages can be sorted into 2 groups:
- Programming languages of higher level (PLHL) and
- Programming languages of lower level (PLLL)

PLHL are logical closer to a human and their application is easier and check and correction of mistakes, faster. PLLL are closer to a computer so programming is harder. Advantage is that programming code is shorter so its execution is much faster and it demands less computer resources such as, processor, mount of RAM memory, capacity of HDD, etc...

For those reasons PLLL are interested for military applications. Most popular representatives of PLLL are assembler and machine language while programming languages C, C++ and C# are programming languages that have good sides of PLHL and PLLL. PLLL can directly access to specific bits inside byte of data, which is key ability for their success in industrial and military purposes.

PLHL

They have been developed for long time period and thay have specialized for surtain jobs or technical applies.

Most known ones are:

1. Fortran (Formula Translation)
- made for solving of mathematic problems, has large libraries for solving mathematic problems

2. Algol (Algorithm Oriented Language)
- nade for solving mathematic problems but less used than Fortran.

3. BASIC (Beginners All purpose Symbolic Instruction Code)
- made for education of beginners in programming area. Object-oriented and much more complex version is known as Visual BASIC.

4. PASCAL (Turbo Pascal)
- Wide applied programming language with great possibilities which designed prof. Niklaus Wirth. Professionals mostly use advanced version of Turbo Pascal and is Object-Oriented and more powerful version of TP, called Delphi. It is considered that Delphi is better from Visual Basic as much as Pascal is from Q-BASIC.

5. Modula
- this is programming language that developed Niklaus Wirth with very interested logic. It has big number of modules. Every module has one input and output point. Programming is actually just calling modules. Even if language is very interesting and powerful, it is considered that it has late because users are already using TP and C

6. COBOL (Common Business Oriented Lang.)
- is prog. lang. for developing of applications in business in world such as banks, and insurance companies.

7. ADA
- is official language of Pentagon and NATO.

8. LOGO (LISP)
- it is PL made for developing applications of expert systems and simulation of logic. Expert systems are huge programs that deal with special way of systemizing acknowladges of experts form specific areas (medicine, physicists, chemist).

9. C++
- is PL which has good elements of PLLL and PLHL. That means you can directly access to bits in some byte as PLLL, but using IDE and similar characteristics of PLHL. It is complicated for using so they are mostly used by professionals. Big amount of comercial application software is developed and written in c++ (windows, office)

1.4 Basic IT terms

2006-09-05T16:44:00.001+02:00

Basic Terms of IT

1. Hardware - it is set of electonic, electic, electro-mechanic, mechanic parts and components from which is psyhical ralization of computer and it peripherals.

2. Software ("soul", "brain" of computer) - is set of programs, instructions and commands and it is execucet by computer, so computer can get funcional sense and usable value.

3. Operating System (OS) is program or set of programs which enable simple and efficient using of computer resources. Theoreticly computer can work without OS but that kind of work doesn't make some sense because it would be unefficient.

4. Program Languages - are exactly defined set of allowd symbols, instruction and rules by which is defined comunication between human and computer

5. Informatics - is scientific-technic discipline which studies and applies IT and theory of information.

6. Information - isdata that can use in proces of making decision when solving some problem. Mesure of our acknowlages about some problem is amount of information we have.

7. Information system - presents organised way of collecting, editing and distribution of information to users that are interested in. That means it is planned using of human and technical potencials with exactly specified goal. Global information systems are: radio,TV, print/newspapers, internet etc. Besides as local information systems can be computer networks, newsboards, school papers etc.

8. Theory of information - is scinet-technical discipline which is doing analysis and exstraction of information from big amount of datas. Usualy sources of information present big amounts of datas, suspicious ones. By analytic way in that big amout of datas, usable and quality information needs to me marked

1.3 Global structure of PC

2006-09-05T16:43:00.001+02:00

PC (Personal Computer) are dominanting in todays market of IT equipment because they have to offer wide compromise of price and abilities. There are a lot better and a lot of more expencive solutions (graphics work stations, main frame computers). There are also weaker of PC (IPOD, PocketPC). Structure of PC we'll consider in spirit of Von Neumann model aldo PC has components that Von Neumann couldn't predict (multimedia applications).

Basic Input unit today makes combination of tastature and mouse. Other input devices through which computer does big amounts of datas are scaner, digitalizer, ligh pen, digital photo-devices and cameras, A/D convertor, modems(transmit). As output devices, most used ones are monitors. Long time it was printer. Rest output devices are: plotter, NCR, D/A convertors, modems (sending).

Systems of mass memory storage are used for long time period archiving of big sizes of datas. Those are: HDD (Hard Disk Drive), CD-ROM (Compact Disk), DVD (Digital Versatel Disk), Streamers, MOD, JAZ, ZIP, LS120. Common thing is that monitors use extreme power supply so they don't consume power from power appling unit from PC.

1.2 Von-Neumann model of computer

2006-09-05T16:41:00.000+02:00

John Von Neumann was famous mathematic scientist of his time and he had done analytcs of all of research till that from subject of numeric machines that are made before todays (his time) computers. He suggested simple concept how should universal Digital Machine should work. He wasn't interested in technical issues and their realization but he sugested global model.

Basic settings of Neumanns model are:
1) There must be import unit that is interface through computer will get import data that needs to be procesed. And also algorithm by which process will be done. Thre must also be output unit by which computer will present results of done process.

2) There must be unit that can execute arithmetic and logic operations and can make decisions (todays CPU)

3) datas and instructions are memored in same form so in specific surcomstances instructions can be treated as datas and vice versa. This is fundamental setting aldo it doesn't seem at first thaught and it was one of main setting that affected later development of computers.

Besides that Von Neumann suggested using a binary number system, but that isn't considered as fundamental setting because computer could workd with other number base. Mathematically can be shown that optimal value of base would be e=2,714 (base of natural logarithm). Technicaly isn't accepting that base is not rounded number. Closest round number is 3 so computer would work faster and more efficient with base 3. But, there isn't any cheap unit that has 3 stable conditions, thats why 2 is accepted as best solution. Von Neumanns model is also called sequencial because program is executed as sequence (array of instructions) by exact order, which is always interpreted as "tight neck" so that connection is called Neumanns defile.

1.1 Basic Ways Of Applying Information Technologies

2006-09-05T16:39:00.001+02:00

By the expansion of globalization, cause of it, practically states and economic borders are dissapearing and where production potencial of all countries are fighting for their place on globar market, IT significants is bigger. Computers are entering into new era of production and surveing part of market giving a lot more options for those companies that are using them. That means for no matter what is comanys orientation and job, its global market ability are very dependant with using IT. Power of american industry and americans military potencial are basing on IT technologies. Production capaciteits are dislocated in less developed countries with cheap workforce but main headquarters are located in USA.

Intro

2006-09-05T16:37:00.000+02:00

In this few tens of posts I will present almost everything about hardware. But unlike most of sites I will talk how do those stuff work and whats theirs history of development. For example I will not talk about which processor is better, but I am going to say what are acctualy those procesors, which technology they use etc..

Bye4now