Important notes for money savings
More interested now? We think you should be. Let us give you an example of data compression application that you see every day.
Exchanging faxes every day is one of those inevitable tasks of every business. As we have recently learned, FaxOnDemand features are more efficient then regular mail. But fax devices would not work without data compression algorithms.
The image of your document is not being sent over the phone line as is. Fax compresses the data before it sends it to reduce the time needed to transmit the document. This reduces the cost of transmission 10 or more times. Now imagine there is no data compression. Your 50- cent fax transmission would cost 5$.
But this is the simplest example of data compression. There are many other applications where you could use data compression to save money.
You should look around and see that you are not spending extra for no reason. We will give you few hints where to look for:
- How are you storing documents, reports, spreadsheets on your computer? You should use compressed format.
- How are you sending email attachments? You should use compressed format.
- How are you watching your TV channels?
“Kompresija podataka”. Zvuči vrlo pametno, nešto što je teško razumjeti. No u stvari je upravo suprotno. Iako toga možda niste svjesni, kompresija podataka prisutna je u mnogim oblicima u vašem svakodnevnom životu.
No, Vi se možda već pitate: “To je sve lijepo, ali zašto bi kompresija podataka bila meni zanimljiva?” Odgovor je vrlo jednostavan.
KOMPRESIJA PODATAKA VAM ŠTEDI NOVAC.
Nadamo se da je sada Vaš interest porasao. Pogledajmo primjer jedne aplikacije koja koristi kompresiju podataka.
Slanje i primanje fax dokumenata svakodnenica je svakog poslovnog èovjeka i firme. No fax uređaji ne bi bili tako rasprostranjeni da se ne koristi kompresija. Naime, dokument se ne šalje preko telefonske linije u svom izvornom obliku. Fax uređaj kompresira podatke prije nego ih šalje a na drugoj strani fax ureðaj obavlja dekompresiju prije nego ispisuje dokument na papiru. Takav postupak smanjuje telefonske troškove 10 pa i više puta. Zamislimo da nema kompresije podataka. Cijena slanja dokumenta fax-om umjesto 5 kuna koštala bi 50 kuna.
No, to je samo jedan od najjednostavnijih primjera kompresije podataka. Postoje mnoge druge aplikacije koje takoðer koriste kompresiju i koje Vam mogu donijeti uštede. Potražite oko sebe primjere gdje bi mogli uštedjeti koristeæi kompresiju podataka.
Mi ćemo Vam pomoći sa nekoliko primjera:
- Kako spremate Vaše stare dokumente, izvještaje, tablice, ugovore sa Vašeg računala. Trebali bi koristiti kompresirani format.
- Kako šaljete priloge u elektronskoj pošti? Trebali bi koristiti kompresirani format.
- Kako gledate televizijske programe?
Cryptography saved my life
Would you give access to all your data cabinets, including the ones with confidential data to some newly hired employee? Of course not, but that’s exactly what you are doing if you leave your digital data lying around unprotected. Suppose thieves break into your company and steal your backup media or even your computers.
>Now what happens? The bad guys have access to your correspondence, financial and personal data, future plans etc. If your computers are connected to the Internet, they even don’t need to get into the office, it can be done from any place across the world.
It’s clear why you should do more than lock your office every night and backup your data every weekend. It’s not enough. There are many ways of good data protection, and one of the best you can get is encryption. It is the transformation of data into a form unreadable by anyone without a secret decryption key. Now when those intruders get their hands on your hard disks or tapes, all they get is a pile of useless information.
One of the best applications utilizing public key cryptography is Pretty Good Privacy by Philip Zimmermann. PGP uses public key encryption to protect your E-mail and data files. It is well featured, fast, and secure. Best of all it’s free for all non commercial use.
Experimental reference center on cryptographical data protection located at the Faculty of Electrical Engineering and Computing is established under the auspices of the Ministry of Science and Technology and the CARNet project. The main goal is PGP support to CARNet users. By supporting this project Republic of Croatia has become one of the few countries in the world to encourage use of cryptography in network communications.
Why Electronic Payment is Important Issue?
Development of electronic communications brought to a very widespread utilization of networked computer systems. The networks have also caught the imagination of people who can see the potential for new ways of conducting businesses such as Electronic Payment.
However, the inability to charge the services has cut down businesses to plain-old advertising or eventually to using credit-cards or neutral third parties to process transactions.
By the way, with the means of payment now employed certain issues arise, both for the users and for those conducting their businesses on the networks – much concern has been focused on credit card authorization and many are worried about business transactions in general.
To create electronic means of payment now emerges as a possible solution, arousing great interest but also giving rise to doubt, even fear, over security issues and possible abuses.
Razvoj elektroničkih komunikacija donijela je do vrlo rasprostranjenog korištenja umreženih računalnih sustava. Mreže su također probudile maštu ljudi koji mogu vidjeti potencijal za nove načine obavljanja poslovanja.
Međutim, nemogućnost naplaćivanja usluge je uticala na tvrtke da budu orjentirani prema običnom starog oglašavanje ili eventualno korištenju kreditne kartice ili neutralne treće strane za obradu transakcija.
Bilo kako bilo, kao sredstva plaćanja sada su nastali određeni problemi, kako za korisnike tako i za one koji vode svoje poslovanje na mreži – mnogo interesa je usmjereno na autorizaciju kreditne kartice i mnogi su zabrinuti zbog poslovnih transakcija u cjelini.
Za stvaranje elektroničkih sredstava plaćanja sada izvire kao moguće rješenje, izazvavši veliki interes, ali i dovodeći sumnju, čak i strah, u vezi sigurnosnih problema i mogućim zlouporabama.
Advanced Tools and Languages for Microcomputer Architecture Simulation (ATLAS)
Overall Organization of ATLAS
The program package ATLAS (Advanced Tools and Languages for Microprocessor Architecture Simulation) consists of several tools. The most important are COMPAS (Configurable Microprocessor Architecture Simulator) and CONAS (Configurable Assembler). The system which we want to simulate with COMPAS, and also the assembly language for CONAS must be described with the C-like specification languages. ATLAS is written in C and available on UNIX. There is a book about ATLAS (in Croatian).
Picture 1: Snapshot of the main window of the ATLAS
What Can Be Done with ATLAS
ATLAS is intended to be an auxiliary tool for simulation and investigation of microprocessor architecture, especially in the first stages of development and logical model testing. Another important usage of ATLAS is in education. By using ATLAS, students can easily study microprocessor architecture and its functionality. In simulation and education ATLAS can cover wide range of problems like assembly programming, microprogramming, I/O transfer, interrupts etc.
Of course, any kind of digital system can be simulated as well. Each system consists of subsystems, called components (e.g. processors, memories, i/o units etc.). Components are described with the COMDEL language (Component Description Language). Components are connected in the system that can be simulated with the SYSDEL language (System Description Language). Already described components, systems and assembly languages are organized in libraries and can be easily used, combined or included into the new system. The specification is possible with the different level of details – depending on user needs.
Additional examples of description files for a special purpose microprocessor called Circlegen are available.
Model debugging is also supported, This is particularly important because model components works in parallel and that would make debugging very difficult if there is no built in support.
The simulation can be performed continuously or step-by-step with the system state tracing. In trace mode it is possible to display the current state of processor registers, instruction that is currently under execution, etc. The dynamic graphical display of bus states and states of other locations in the system (e.g. pins, registers, memory locations etc.) is possible. Breakpoints are easily set in assembly programs. The performance measurement, analysis and comparison between different systems or between different versions of one system are also supported.
In order to use CONAS (configurable assembler), a description of an assembly language and its translation into a machine code should be written in ADEL (Assembler DEsrciption Language). This description has a form that resembles instruction tables usually given for comercial microprocessors.
Whole ATLAS is organized to be easy-to-use and flexible. The arbitrary number of ATLAS tools can be started from UNIX shell, X Window System or any other ATLAS tool. Detailed help facility is available in every tool and quick-help is available for popups.
- An accurate description of the digital system
- High simulation speed
- High-level components are easily described on behavioural level
- Easy to use user-friendly graphical interface
- Context sensitive help facility
- Adaptability of the program to the user’s habits
- Requires very small amount of your disk space
- Available on UNIX and X Window System
- Works not only on workstations but also on X-terminals and X-terminal emulators on PCs