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By Professor Omar Hasan Kasule Sr.



1.1.1 Ancient times: Humans since time immemorial have used some devices for storing data and making simple computations. A herdsman would for example collect and keep one stone for each sheep that he had. He would add more stones to the collection as more sheep were born. He would also drop some stones if some of the sheep died or were lost. Some would tie knots on their cloth or on a string with each knot representing either one quantity or several quantities. The Chinese discovered the abacus for making arithmetic computations easier. It is still used in parts of China and other parts of the world. Other civilizations developed similar computing devices.


1.1.2 Earliest computing machine: The history of computing reads like a fairy tale. Developments have been very rapid. In 1882 John Shaw Billings invented the Hollerith punched card for processing US census results. This was the first computing machine of modern times. The Hollerith Company later became the famous International Business Machines (IBM).


1.1.3 The first computer: The Electronic Numerical Integrator and Calculator (ENIAC) were invented after World War II for ballistic calculations. It had 17,000 vacuum tubes and used an amount of electricity sufficient to 175 houses. The pace of development is such that today’s desktop PC is faster that ENIAC. ENIAC is the dinosaur of the computer revolution.


1.1.4 Mainframe and minicomputers: The first computers were big structures available only in the largest institutions. In 1963 The National Medical Laboratory (NLM) developed Medlars/Medline and moved it to an IBM360 computer in 1965.


1.1.5 Personal computers: Digital developed the first personal computer called PD98 in 1965. The development of personal computers was the real computer revolution because it led to widespread availability of computers in homes and offices. This increased access of ordinary people to computing.


1.1.6 Modern-day toys: laptops, notebooks, ipod, etc



1.2.1 Types of computers: Computers come in various sizes and grades of complexity: microcomputers, minicomputers, mainframe computers, and supercomputers. Microcomputers are either desktop or portable. The Portable ones are laptops, notebooks, sub-notebooks, and the personal digital assistant. Computer hardware has the following components: (a) input devices: keyboard and mouse (b) system unit which consists of the central processing unit and the memory (random access or secondary storage). (c) Output devices: the monitor or video display screen and the printer. (d) Communication devices such as the modem. The trend of downsizing will continue. The electronics industry will pack more computing power in increasingly smaller units. The range of applications will broaden. Pen-based computing will become possible.


1.2.2 Input devices: Character input devices are of two types: keyboard and direct. The keyboard has three types of keys: typewriter keys, functional keys, and numeric keys. There are several direct input devices: the mouse, the touch screen, the light pen, the image scanner, the barcode reader, the magnetic link recognition as is used in bank or smart cards, and optical mark recognition. Voice input devices can either recognize continuous speech or discrete words


1.2.3 Output devices: There are three types of character output devices: monitors, printers, and plotters. Monitors can be VGA, SUGA, and XGA. They may come in a standard form, as desktop, and as portable monitors. HDV monitors have started appearing. Printers can be dot matrix, inkjet, laser, or thermal. Voice output devices enable a computer to pronounce a printed word.


1.2.4 Central processing unit / the computer chip: The central processing unit (CPU) is the calculating part of the computer. The CPU in a personal computer is a single electronic component called the microprocessor chip. The chip is the control unit that tells the computer how to carry out a program’s instructions. The arithmetic logic unit carries out arithmetic operations such as addition, subtraction, division, and multiplication. It also carries out logical operations like inequalities, < or < and the equality =. Data is stored as binary units either 0 or 1. Each ‘0’  or ‘1’ in the binary system is called a bit. Eight bits are combined to make a byte. A kilobyte, abbreviated as KB or K-byte, is equivalent to 1024 bytes. A megabyte, abbreviated as MB pr M-byte, is 106 bytes. A Gigabyte, abbreviated a BG or G-byte, is 1 billion bytes. A terabyte, abbreviated as TB or T-byte, is 1 trillion bytes. There are 4 types of random access memory: conventional is up to 640 KB, upper memory 640KB to 1 MB, extended memory is over 1 MB, and expanded memory. Some memory is read only ROM.


1.2.5 File storage and retrieval in the computer: Data in a computer is stored as files that are grouped in directories. The files may be arranged sequentially or may be accessed randomly. In the sequential arrangement, records are stored physically one after the other. In random access any record is directly accessible. The index file is a compromise between the two extremes. Each file in turn consists of records that may be in a fixed format or a free format. If the format is free there is need for instructions to enable correct reading and separation of the variables. Files may be master files containing permanent data or transaction files. Query languages are used to access data. They use commands such as display, add, compare, list, select, update.


1.2.6 Computer memory: The random access memory keeps data during the processing stage. The memory is either random access memory (RAM) or secondary storage. Secondary storage or long-term memory is either or the hard disk or some form of external storage such as floppy disks, optical disks, magnetic tape, and the compact disk. The hard disk may be an internal hard disk, a hard disk cartridge, or a hard disk pack. The compact disk may be read only CD-ROM or may be recordable, CD-R.


1.2.7 Connectivity: There are many ways of connection between information centers: fax machines, electronic bulletin boards for messaging, electronic mail, voice messaging, shared resources by uploading or downloading, and online services. The modem is an acronym for modulator-demodulator. It is used to transfer data from one point to another. Modem speed is measured in bits/second. Modems come in various forms: external modems, internal modems, wireless modems, and fax modems. The communication channels between and among computers can be telephone lines, co-axial cables, fiber optic cables, and microwaves over short distances, and satellites as relay stations for microwaves. Computers may be interconnected in a local area network, LAN; a metro area network, MAN; or a wide area network, WAN.


1.2.8 Ergonomics: Many people spend a big portion of the working day sitting at a computer terminal that leads to physical and mental stress. The physical problems are eyestrain that causes headache, back and neck pain, repetitive injury of the wrist and fingers, and the effects of the electromagnetic radiation from the screen. Noise and excessive monitoring lead to mental stress.




1.3.1 Definition and types of software: The software is the operating system and the application programs. The programs are written in several computer languages (basic, FORTRAN, C, and Pascal). A program sets out the statistical method step by step. A statistical package is a collection of programs.  There are three types of software: operating systems, general-purpose programs, and futuristic programs.


1.3.3Operating systems: Operating systems are DOS, Windows, OS/2, Macintosh, and UNIX. They operate the machine.


1.3.4 General purpose programs: General-purpose programs are word-processing, database management, statistical software, spreadsheets, graphics software, communication software. The following are the most popular statistical packages and the years of their introduction: BMDP in 1961, SPSS in 1970, Minitab in 1972, Censtat in 1972, SAS in 1972, and GLIM in 1974. Epi-info and Egres are specific for epidemiology. SAS first appeared in ?1976 and was available on PCs in the 1980s. Epi-info was released in 1985.


1.3.4 Specialized programs: Graphics software is of three types: analytic graphics, presentation graphics, and drawing programs. Communication software allows access and exchange of information. Multimedia or hypermedia are used in games. Futuristic programs are already available as the personal information manager, groupware coordinating people, project management software, desktop publishing, and multimedia.


1.3.5 Artificial intelligence: Artificial intelligence is an attempt to simulate human thought and actions. Artificial intelligence is used in three areas: robotics, expert systems, and virtual reality. Robotics may be industrial doing repetitive jobs that humans find boring. Some robotics are perceptive with sensory functions. Other robotics are mobile and are used in various ways including recreation. Knowledge-based or expert systems are programs that incorporate the human thought or problem-solving processes. They use human logic in problem solving and follow probability rules using probability trees. Artificial intelligence programs search systematically for a solution by looking through many alternatives and choosing the best. The best programs are those that are able to focus on the more plausible alternatives. These programs require a knowledge base. They work by first reducing a big problem into smaller more manageable problems. The problem may be restated in another way to make the solution easier. Virtual reality is also called artificial reality or virtual environment is used in entertainment and simulators that train pilots.




All organizations generate and use a lot of data. Many managerial and planning functions are based on information in the database. A lot of data operational is generated. For example a hospital schedules a lot appointments and surgery. There is a lot of billing and financial data. A lot of this data is now computerized. The invention of the computer enabling humans to handle large amounts of data has created an information revolution. New computers can manage (collection & storage) and analyze large amounts of data, a feat that was unthinkable a few years ago.


2.2 Components of an information system: An information system has 5 components: people, procedures for example computer manuals, software (system software or applications software either custom-made or packaged), hardware, and data.


2.3 Database management systems: Database management systems create. Modify, and access data. Database management systems serve the following purposes: sharing data, security of data by use of passwords, and data integrity. The database management system has an element as basic building block. Several element values are arrayed as a single observation or record belonging to say one person. Several observations are put together to make a rectangular file showing values of variables for several individuals. Several files make a database. A data dictionary describes the structure of the data. Several types of databases can be identified depending in the architecture of information storage in the computer. A relational database is one in which all fields are related by the identifying variable. It is in the form of a table with rows and columns. A hierarchical database is several layers of information such that lower layers are not reached before higher ones are opened. The hierarchical database is a one-to-many arrangement. There are parent and child nodes. In searching for an item you start at the top and go deep into the data. A network database is a many-to-many architecture. An item can be reached in more than one way.


2.4 System analysis and design: The following are the various functions of a system analyst: system analysis, system design, system development, system implementation, and system maintenance. The setting up of a database or a transactional computer system is a highly intellectual exercise that requires full understanding of all operations of the organization, the routine and the exceptional ones.


2.5 Computer programming: A program is a series of instructions that the computer executes. There are 6 steps in programming: program specification which states the objectives, the input and the output; program design which indicates the logic structure by means of flow charts to show all steps from input through processing to output; coding is the actual writing of the program at the computer terminal using a programming language; program testing or debugging is correction of syntax and logic errors; documentation is stating the purpose and process of the program; and program maintenance is development and improvement. Software engineering tools help produce more efficient programs. There are 5 generations of programming languages. Machine language is the binary code. Assembly language is still in binary code but is more readable than machine language. High level procedural languages like BASIC, Pascal, C, COBOL, and FORTRAN are source codes converted by the machine into machine language (also called object code). Problem oriented languages are query languages used in searching databases. Natural language is usual human language.


2.6 Ethical problems: Ethical issues of privacy, accuracy, data ownership, data access, and security arise due to the large amount of personal information now kept on computers. Computer hackers who gain entrance to databases and cause havoc commit computer crimes. Viruses attack and destroy databases. Encryption is used to decrease the chance of stealing data in transit. Restriction of access using passwords also helps keep away intruders.




Measurement and counting are very important because quantitative information is the basis for growth of science and technology. Thinking is more effective and more logical when objects can be quantified exactly. Mathematics is a universal and exact language of scientific communication. Statisticians invoke the curse of Kelvin that states that if you cannot express it in numbers you do not understand it[1]. We are now living in the age of information and numerical data. There is a lot of quantitative medical, health, clinical, laboratory, radiological information that has to be digested, summarized, understood, and used. Medicine is increasingly quantitative with many parameters of disease and health being measurable. Quantitative description using numbers is superior to qualitative description. Medical research requires statistical methods in the design and analysis of studies.



Health Information Systems (HIS) have witnessed great changes recently. We have shifted from paper-based to computer-based processing and storage. There has been a shift from alpha-numeric data to storing images. Data is available to a wider range of end-users because of easier access. Data is used not only for clinical management but also for research and policy making. More sophisticated developments can be envisaged in the future. Computer-based patient record systems (CBPRS) can have a positive impact on medical practice, quality of care, and user and patient satisfaction. Patient data is entered into a computer at the bed side as the physician examines. The physician can also access previous data about the patient easily. CBPRS however introduces new problems of their own because they interfere with doctor-patient communication while the doctor is busy using the computer. Radiological images and laboratory data can be stores online and can be accessed instantly by caregivers in various parts of the hospital. The ability to store data electronically helps save floor space that before was used to store paper records. Online medical records have the further advantage of integrating all records of one patient (clinical, laboratory, radiological etc). Integrated records reduce errors in patient identification and management.



Patients who require continuous monitoring can be hooked onto monitors that feed into ‘intelligent’ computers. The computers analyze the monitoring data and will generate a signal to call the clinician if there is a problem. This helps free up some of the caregivers’ time and can enable one care giver to look after several patients at the same time without compromising on quality of care.



Clinicians on the ward may enter their prescription orders directly into the computer and they reach the pharmacy instantly. This Computerized Physician Order Entry (CPOE) can help reduce physician errors if combined with a decision-support system (DSS) that checks the appropriateness of the prescription using guidelines stored in the hospital data-base. Besides speed and quality control, CPOE do away with the traditional paper-based hospital systems.



IT can facilitate communication in medicine in many ways. Patients suffering from chronic diseases can communicate with one another online and be able to exchange information and give each other psychological support. Patients can communicate with care providers online . Telemedicine enables caregivers in different places to communicate and consult on patient management. Electronic Data Interchange (EDI) among health professionals improves the quality of health care bit may involve invasion of privacy and unintentional information disclosure.



IT helps clinical decision making in many ways. Physicians can access previous patient data easily if they need it in making a new decision. They also can practice evidence-based medicine by looking for published sources on dealing with specific cases. What is even more exciting is the use of clinical decision support systems (DSS) based on Bayesian probability to reach a probable diagnosis. Baye’s theorem enables combining new empirical data with evidence already available to reach a conclusion. For example if a decision has to be made whether a patient has a disease, D, on the basis of a laboratory test, T, we can use the Bayesian formulation as follows: Pr (D+|T+) = {Pr (T+|D+) Pr (D+)} / {Pr (T+|D+) Pr (D+) + Pr (T+|D-) Pr (D-)}.



Use of IT to collect and analyze operational data in hospitals and clinics can enable policy making. Online Analytical Processing software can empower managers to make decisions quickly and effectively. It summarizes and processes operational data in real time and provides a broad picture of what is going on in the individual patient or in the while medical care system.



Practical problems arise in the scheduling of reception and treatment of patients in a busy hospital. Patients should not be made to wait for very long. In the same way caregivers cannot be paid to sit and wait for few patients who turn up. Achieving a balance between the two objectives requires sophisticated analysis based on probability theory. Two basic parameters involved, arrival time and service duration, may be fixed or random. By using probability computations it is possible to arrive at a compromise scheduling that will minimize patient waiting but at the same time ensure that caregivers are not left idle. More sophisticated problems can be tackled such as deciding whether there should be one or several queues in front of 2-5 provider spots. The actual waiting times may not differ very much. The psychological advantage of one line is that there is apparent quick movement within the line. One line also distributes the variety of presenting problems in a random way among the providers. Multiple lines have the advantage that the queue appears shorter. The disadvantage is that those who line up in front of slow providers will wait proportionately longer.



This is a direct application of computer technology in imaging that has revolutionized diagnosis and management of disease.

[1] Feinstein AR (1971): On exorcising the ghost of Gauss and the curse of Kelvin. Clin Pharm Ther 12:1003

Professor Omar Hasan Kasule Sr. November 2005