Angl-kniha

.
The most important program in an OS is the supervisor program. It remains in memory all the time
that the computer is operating, and manages the OS. It loads other parts of the OS into memory when
they are needed. Programs that remain in memory while the computer is in use are known as resident
programs. Programs that only stay in memory while they are being used are known as non-resident
programs.
Some operating systems are command driven (i.e. the user runs a program by typing a command).
The screen is usually blank except for a symbol (e.g. $) which acts as a command prompt. When the
command is typed at the prompt and the Enter key is pressed, the command is processed and the
output is displayed on the screen. OS commands are usually short words or abbreviations (e.g., date,
logout, passwd, ls).
Unix is a command driven operating system used on all sizes of computers, but mostly large multi-
user, multi-tasking mainframe computers. It is available in many versions, such as Linux, Minix, HP-UX,
Xenix, Venix, Ultrix, A/UX, AIX, Solaris, and PowerOpen. Other command driven operating systems
mentioned in this unit include: VAX/VMS, MVS VM OS/390, NetWare, MS-DOS and PC-DOS.
Some operating systems have a GUI (pronounced like 'goo-ey' - graphical user interface) that
allows the user to use a mouse to click on icons on the screen or choose commands from a list of
choices known as a menu. Operating systems with graphical interfaces mentioned in this unit include:
MacOS, OS/2, Penpoint, Windows NT, Windows 3.x, Windows 9X and Windows 2000.
READING
A conceptual diagram of an operating system
Closest to the user are applications programs - software that helps a user compute a payroll or play a
game or calculate the trajectory of a rocket.
The operating system is the set of programs between the applications programs and the hardware.
Operating Systems: Hidden Software
When a brand new computer comes off the factory assembly line, it can do nothing. The hardware
needs software to make it work. Are we talking about applications software such as wordprocessing or
spreadsheet software? Partly. But an applications software package does not communicate directly with
the hardware. Between the applications software and the hardware is a software interface — an
operating system. An operating system is a set of programs that lies between applications software and
the computer hardware.
The most important program in the operating system, the program that manages the operating
system, is the supervisor program, most of which remains in memory and is thus referred to as resident.
The supervisor controls the entire operating system and loads into memory other operating system
programs (called nonresident) from disk storage only as needed.
An operating system has three main functions: (1) manage the computer's resources, such as the
central processing unit, memory, disk drives, and printers, (2) establish a user Interface, and (3)
Execute and provide services for applications software. Keep in mind, however, that much of the work of
Page 11 from 33 VB035 English I
an operating system is hidden from the user. In particular, the first listed function, managing the
computer's resources, is taken care of without the user being aware of the details. Furthermore, all input
and output operations, although invoked by an applications program, are actually carried out by the
operating system.
SPECIALIST READING
LINUX
Linux has its roots in a student project. In 1992, an undergraduate called Linus Torvalds was
studying computer science in Helsinki, Finland. Like most computer science courses, a big component
of it was taught on (and about) Unix. Unix was the wonder operating system of the 1970s and 1980s:
both a textbook example of the principles of operating system design, and sufficiently robust to be the
standard OS in engineering and scientific computing. But Unix was a commercial product (licensed by
AT&T to a number of resellers), and cost more than a student could pay.
Annoyed by the shortcomings of Minix (a compact Unix clone written as a teaching aid by Professor
Andy Tannenbaum) Linus set out to write his own 'kernel' — the core of an operating system that
handles memory allocation, talks to hardware devices, and makes sure everything keeps running. He
used the GNU programming tools developed by Richard Stallman's Free Software Foundation, an
organization, of volunteers dedicated to fulfilling Stallman's ideal of making good software that anyone
could use without paying. When he'd written a basic kernel, he released the source code to the Linux
kernel on the Internet.
Source code is important. It's the original from which compiled programs are generated. If you don't
have the source code to a program, you can't modify it to fix bugs or add new features. Most software
companies won't sell you their source code, or will only do so for an eye-watering price, because they
believe that if they make it available it will destroy their revenue stream.
What happened next was astounding, from the conventional, commercial software industry point of
view - and utterly predictable to anyone who knew about the Free Software Foundation. Programmers
(mostly academics and students) began using Linux. They found that it didn't do things they wanted it to
do - so they fixed it. And where they improved it, they sent the improvements to Linus, who rolled them
into the kernel. And Linux began to grow.
There's a term for this model of software development; it's called Open Source (see
www.opensource.org/ for more information). Anyone can have the source code — it's free (in the sense
of free speech, not free beer). Anyone can contribute to it. If you use it heavily you may want to extend
or develop or fix bugs in it — and it is so easy to give your fixes back to the community that most people
do so.
An operating system kernel on its own isn't a lot of use; but Linux was purposefully designed as a
near-clone of Unix, and there is a lot of software out there that is free and was designed to compile on
Linux. By about 1992, the first 'distributions' appeared.
A distribution is the Linux-user term for a complete operating system kit, complete with the utilities and
applications you need to make it do useful things - command interpreters, programming tools, text
editors, typesetting tools, and graphical user interfaces based on the X windowing system. X is a
standard in academic and scientific computing, but not hitherto common on PCs; it's a complex
distributed windowing system on which people implement graphical interfaces like KDE and Gnome.
As more and more people got to know about Linux, some of them began to port the Linux kernel to
run on non-standard computers. Because it's free, Linux is now the most widely-ported operating system
there is.
UNIT 7 Graphical User Interfaces
INTRODUCTION
A user interface allows a user to interact with a computer. In particular, a GUI (graphical user
interface) allows the user to use a mouse to interact with the computer. Microsoft Windows
(commonly referred to as Windows) is a common GUI used on PCs (IBM compatible personal
computers). The main Windows background screen is called the desktop. Programs, files and folders
are represented on the desktop by small images called icons. Using a mouse, the user can move a
pointer (cursor) across the screen. An icon can be selected by clicking the left mouse button (i.e.
Page 12 from 33 VB035 English I
quickly pressing and releasing the button). By holding the pointer over an icon (hovering), a text box
can be made to appear that explains what the icon represents. This text box is known as a tooltip.
Double-clicking the mouse (pressing and releasing the button twice in quick succession) causes the
program, file or folder represented by the icon to open in a rectangular box on the screen called a
window. More than one window can be open at a time but the one with the focus is known as the
active window. Windows can have a vertical scroll bar and a horizontal scroll bar to allow the user to
move a document up and down or across the screen respectively. A user can drag a selected item from
one part of the screen to another by holding down the left mouse button while moving the pointer. The
user can then drop the item at the new location by releasing the mouse button.
Commands are displayed in a menu bar along the top of the window. Clicking on a command opens
a list of choices known as a menu. Clicking on a menu item sometimes opens another related menu
called a submenu. Common commands include:
Find searches for a word, filename, or folder name
Undo reverses the last action of the user
Cut deletes the selected text, file or folder and copies it to a special area of memory
called the clipboard
Paste inserts the text, file or folder stored in the clipboard, at the location of the cursor
A bar, known as a taskbar, is displayed along the bottom of the desktop showing what programs, files
and folders are currently open. At the far right of the taskbar is a special area called the system tray
where icons are displayed showing what resident programs are continuously-running in the background
e.g. the system clock or a sound volume control. There is a Start button at the far left of the taskbar.
When the Start button is clicked, the Start menu opens on the screen. The user can close down the
operating system by choosing the Shut Down option on the Start Menu. A touchscreen allows the user
to select icons and commands by touching the display screen with their finger instead of using a mouse.
Graphical user interfaces were first introduced with the Apple Mac OS. Other GUIs with desktops, icons,
pointers, windows, menus and submenus are also available.
Common icons on the Microsoft Windows desktop include:
Microsoft Outlook a messaging program
My Briefcase a program that allows the user to exchange files with a portable computer
and to synchronise the files on each computer
Network
Neighbourhood or My
Network Places
a feature that displays the names of other computers networked with yours
My Computer a feature that lets you see the resources on your computer
Internet Explorer a browser program that allows the user to view webpages on the Internet
Recycle Bin a feature that stores deleted files and allows the user to restore them to
their original location i.e. the equivalent to the trashcan on an Apple Mac
system.
A + sign used between the names of keyboard keys means that the user should press both keys
simultaneously e.g. ALT + TAB. Keyboard keys and combination of keys mentioned in the text include:
Shift key allows you to type in upper case (capital letters)
MouseKeys feature enables you to use the numeric keypad to move the mouse pointer
ALT + TAB allows you to switch between open programs
StickyKeys feature helps disabled people to operate two keys simultaneously
PRINT SCREEN key lets you copy an image of the whole screen to the Clipboard
ALT + PRINT SCREEN lets you copy an image of the active window to the Clipboard
READING
Menu bar
Just about all programs display a menu bar across the top of the screen, including the 'Finder'. The
menu bar will change, depending on the program you're running at the time.
Document
This is a text file which tells us something about the contents of this CD-ROM. You can read it by
simply double-clicking on it - your iMac will then automatically find the program needed to open it.
Page 13 from 33 VB035 English I
Application
This is an application, or program icon. Double-clicking on it will start the program. It's not always
obvious whether an icon is for a document or a program, but you soon get to be able to spot these
things.
Folder
This is a folder icon, and these all tend to look the same - like a kind of 3D view of a suspension file.
Sometimes they're adorned with other graphics, but they're usually pretty easy to spot. Double-clicking
on a folder icon displays that folder's contents in another window, which is what we've done here.
Hard Disk icon
Folders; files, documents and other items are displayed as little icons like this. This one, in fact,
represents your iMac's internal hard disk.
CD-ROM icon
Your hard disk icon (and Wastebasket icon) may be the only ones you see on your desktop. If you
insert a CD-ROM, though, it will appear as an icon on your desktop too. We've double-clicked on it to
display its contents. To eject a CD, by the way, you have to drag its icon onto the Wastebasket - you
can't just press the CD-ROM drive button. If you do, you'll be waiting an awful long time.
Folder window
When you double-click on a folder or a disk drive, its contents are displayed in a window like this one.
These contents can be documents, programs or other folders.
List view
This is another folder window, but this time we're looking at the contents in 'List' view. Otherwise, it's
the same as the window next to it - a 'window' on a folder, basically. You can nest folders many layers
deep, in case you're wondering, and you're likely to get confused long before your iMac does - try to
keep your filing system as simple as possible.
Menu/menu option
To open a menu, click on its name in the menu bar. This displays a drop-down list like the one you
see here. To choose one of the menu options, just click on it (the options are highlighted as the mouse
pointer moves over them to help you get the right one). Don't forget to always shut down your iMac via
this menu, NOT by simply switching the power off.
Control Strip
The Control Strip offers quick access to many of your iMac's settings like the speaker volume, sound
input and CD player controls. Until you've found out what these gadgets do, you can 'hide' it by clicking
on the small ribbed area to the far right. This reduces it to a little handle in the bottom left-hand corner of
the screen. Click this handle if you want to display the Control Strip again.
Scrollbar
You'll see these gadgets whenever the contents of a folder won't fit in the window, You click on either
the horizontal or vertical scroll arrows to display more of the contents - either that, or drag on the little
blue 'Scrollbox'.
Desktop pattern
This background image can be swapped for many more via the Appearance control panel. You can
use a repeating 'pattern' like this, or a single image - a scanned photograph for example.
Wastebasket icon
The Wastebasket is where you throw things you no longer need. It doesn't empty straight away,
(though as you can see, ours is so full the lid's fallen off), so you can change your mind if you have to.
When you want to eject a disk, be it a CD-ROM or a floppy disk (if you've got a floppy disk drive
attached), you drag its icon on to the Wastebasket and the iMac will spit it out automatically.
Page 14 from 33 VB035 English I
SPECIALIST READING
User interfaces
Cheaper and more powerful personal computers are making it possible to perform processor-
intensive tasks on the desktop. Break-throughts in technology, such as speech recognition, are
enabling new ways of interacting with computers. And the convergence of personal computers and
consumer electronics devices is broadening the base of computer users and placing new emphasis on
ease of use. Together, these developments will drive the indrustry in the next few years to build the first
completely new interfaces since SRI International and Xerox's Palo Alto Research Center did their
pioneering research into graphical user interfaces (GUIs) int the 1970s.
True, it's unlikely that you'll be ready to toss out the keyboard and mouse any time soon. Indeed, a
whole cottage industry - inspired by the hyperlinked design of the World Wide Web - has spring up to
improve today's graphical user interface. Companies are developing products that organize information
graphicaly in more intutive ways. XML based formats enable users to view content, including local and
network files, within a single browser interface. But it is the more dramatic innovations such as speech
recognition that are poised to shake up interface design.
Speech will become a major component of user interfaces, and applications will be completely
redesigned to incorporate speech input. Palm size and handheld PCs, with their cramped keyboards
and basic handwriting recognition, will benefit from speech technology.
Though speech recognition may never be a complete replacement for other input devices, future
interfaces will offer a combination of input types a concept known as multimodal input. A mouse is a
very efficient device for desktop navigation, for example, but not for changing the style of a paragraph.
By using both a mouse and speech input, a user can first point to the appropriate paragraph and then
say to the computer, 'Make that bold.' Of course, multimodal interfaces will involve more than just
traditional input devices and speech recognition. Eventually most PCs will alse have handwriting
recognition, text to speech (TTS), the ability to recognize faces or gestures, and even the ability to
observe their surroundings.
At the Intelligent Room, a project of Massechusetts Institute of Technology's Artificial Intelligence Lab,
researchers have given sight to PCs running Microsoft Windows through the use of video cameras. 'Up
to now, the PC hasn't cared about the world around it.' said Rodnev A. Brooks, the Director of MIT's
Artificial Intelligence Lab. 'When you combine computer vision with speech understanding, it liberates
the user from having to sit in front of a keyboard and screen.
It's no secret that the amount of information - both on the Internet and within intranets - at the
fingertips of computer users that has been expanding rapidly. This information onslaught has led to an
interest in intelligent agents, software assistants that perform tasks such as retrieving and delivering
information and automating repetive tasks. Agents will make computing significantly easier. They can be
used as Web browsers, help desks, and shopping assistants. Combined with the ability to look and
listen, intelligent agents will bring personal computers one step closer to behaving more like humans.
This is not an accident. Researchers have long noted that users have a tendency to treat their personal
computers as though they were human. By making computers more 'social,' the hope to also make them
easier to use.
As these technologies enter mainstream applications, they will have a marked impact on the way we
work with personal computers. Soon, the question will be not 'what does software look like' but 'how
does it behave?'
Page 15 from 33 VB035 English I
VB036 English II
UNIT 8 Applications Programs
INTRODUCTION
Software is the word used to refer to programs (sets of computer instructions written in a computer
language) and data that is input, processed and output by a computer system. Applications programs
are programs that allow the user to do various types of work on a computer e.g. wordprocessors,
databases. A set of related applications programs is referred to as a package (or suite). Common
applications programs include:
wordprocessors for creating and editing texts
spreadsheets for performing calculations using formulas
databases for storing data so that it can be easily searched and sorted
graphics for drawing
games for playing fast action games
accounts for keeping business accounts
payroll for calculating salaries
presentation program for creating multimedia slide shows
email for sending electronic mail messages
PIM (personal information
manager)
for keeping track of appointments, address book, task list, etc.
DTP (desktop publishing
program)
for creating publications to be printed by a professional printer
small business tools for performing various business tasks
website editor for creating and editing webpages
image editor for editing graphic images
developer tools for writing programs to add features to existing applications and
creating integrated program systems
Some applications programs, such as wordprocessors, spreadsheets and databases, are commonly
referred to as office programs because they are commonly used in a typical office. Office packages
(or suites) such as Microsoft Office are sets of interrelated office programs. Different versions of office
suites are usually available containing different combinations of programs. Mailmerging is a useful
feature found in most office suites that combines a database with a wordprocessor document to
automatically produce a copy of a standard letter for each record in the database.
A variety of computer hardware is used in the doctors' practice in this unit including:
PC common name for an IBM compatible personal computer
network computers connected together
file server a powerful computer that stores and allows users access to data files on a
network
laser printer a very high quality text and graphics printer that has a photosensitive drum that
deposits toner powder on the paper
dot-matrix
printer
a low quality printer that prints by hammering pins on the paper to print an image
made up of dots. The hammering action means that it can print on special multipart
paper where a number of copies are produced at the same time.
CD-ROM a compact disk read only memory storage device that is cheap to produce and
suitable for storing large amounts of data
The Patient Browser program (GPASS) discussed in this unit is a type of database for sorting and
searching patient records. To search, you select different option scr