Computer Architecture & Security Concepts

This assignment delves into the core principles of computer architecture, analyzing its influence on operating system performance. It further examines data communications and encryption technologies, highlighting their significance in securing information. The discussion covers topics such as processor design, memory management, network protocols, and cryptographic algorithms.

Name, Student Number 2016/7 KF7023 & EN0705 Network and Operating
Systems
Faculty of Engineering and Environment
KF7023 & EN0705 - Computer Networks and
Operating Systems
Author:
Student number:
Year: 2016/7
Name, Student Number KF7023 & EN0705 Network and Operating Systems

Name, Student Number 2016/7 KF7023 & EN0705 Network and Operating
Systems
I. Evaluation Report
CISC/RISC Design Philosophies and OS Issues
Abstract
This paper looks at the RISC and CISC computer processor architectures in the context of
operating system issues such as performance and architecture. RISC is an architecture that
uses simplified instructions to execute operations in a single clock cycle, while CISC is an
architecture that aims at completing tasks in as few lines as is possible and so uses the MULT
system which is a complex instruction, while RISC breaks down MULT into simple
instructions. For this reason, RISC performs much faster (between 2 and 4 times) when
compared to CISC when running a program such as an Operating System instruction.
Because of simplicity, RISC has an advantage of speed; it performs fast, and is cheaper and
easier to produce; but this also raises ethical issues as RISC focuses on performance and not
protection while leading to increased e-wastes as every new generation of RISC processors
have significantly large and better performance over previous generations. CISC makes micro
programming easy and does not require a complicated compiler; it also uses fewer
instructions for task execution. However, it has the limitation of speed; its comparatively
much slower and complex because it constrains instructions as a subset of previous
generations, leading to complex architectures. It can slow down an OS because different
instructions need different clock times for their execution. Setting condition codes is required
in CISC and these can take a lot of time, and have to be examined
Background
Each processor is built with an ability to execute a given set of instructions to perform a
limited set of fundamental operations. The processor has an instruction set architecture
necessary for creating programs at the machine level to perform any logical and mathematical
computations. This instruction set is embedded within processor and serves as the bridge
between the hardware and software. High level language is translated into machine level
language using a compiler. If there is an increase in the number of complex instructions in the
processor instruction set, the processor working slows down because there is increased
complexity in instruction decoding; this also consumes more time. The most important factor
that impacts software and overall computer performance is the design of the processor
instruction set; it impacts how operating systems are designed and how they run on the
Name, Student Number KF7023 & EN0705 Network and Operating Systems

Name, Student Number 2016/7 KF7023 & EN0705 Network and Operating
Systems
computer processor. This is due to the fact that all software applications and operating
systems are programmed within the processor instruction set boundaries. So for every
processor, a unique instruction set is employed so that one processors’ machine language
programs will not run on a different processor. Computer use processors to carry out
computations; these CPUs have distinct design philosophies, namely RISC (Reduced
Instruction Set Computer) and CISC (Complex Instruction Set Computer). The main goal of
the CISC architecture is the completion of tasks in as few assembly lines as possible. To
achieve this, the processor hardware is built so it can understand and execute a series of
operations; it comes prepared with a specific set of instructions (MULT). Upon execution, the
MULT loads the 2 values into separate registers, multiplies that operation within the
execution unit, and stores the outcome in the appropriate register. In this way, CISC
completes an entire multiplication process using a singe instruction. MULT directly operates
in the memory banks of computers and the programmer is thus not required to explicitly call
any storing or loading instructions. In the RISC approach, only simple instructions that are
executable in a single clock cycle are used, so the ‘MULT’ command described in CISC
above is divided into three commands that are separate; ‘LOAD’ that moves data to the
register from a memory bank, ‘PROD’ that finds two operand products located in the
registers, and ‘STORE’ that moves data to the memory banks from the register. CISC has a
focus on hardware and can perform complex multi clock instructions (Blem, Menon &
Sankaralingam, 2013). RISC on the other hand, has a greater focus on software and operates
in a single clock cycle to execute tasks. The operating systems are designed so as to make the
best use of the underlying processor architecture; its performance in terms of memory
addressing and architecture (layering), as well as its implementation is directly impacted by
the processor it runs on. The performance of operating systems is also impacted by the
processor architecture in the context of the ISA (instruction set architecture). A CISC
processor has several specialized instructions though some are rarely used practically in
operating systems while a RISC processor simplifies things through the efficient
implementation only of the instructions that the operating system uses frequently; RISC
implements the less common operations as subroutines. This approach results in the extra
processor execution time compensated for by their infrequent usage (Burger et al., 2004).
These design philosophies have their merits and demerits in terms of computer performance
and operating system architecture and performance
Advantages
Name, Student Number KF7023 & EN0705 Network and Operating Systems

Name, Student Number 2016/7 KF7023 & EN0705 Network and Operating
Systems
The different architectures have their merits; CISC has advantages in micro programming;
this becomes as easy to implement as assembly language with RISC. Further, micro
programming is far less expensive compared to hard wiring control units. CISC machines
have upward compatibility allowing new computers to run older programs as the new
computer has a set of instructions contained in the earlier computers. It uses fewer
instructions for task implementation, an advantage when the main memory is slow. It does
not require a complicated compiler since instruction sets for micro programs can be written to
match up to high level languages.
The RISC architecture has a number of advantages as well; its main advantage is speed
because it has a simplified instruction set that enables super scalar pipelined design; this
makes them achieve between 2 and 4 times the CISC processor performance when
comparable semi conductor technology as well as similar clock speeds are used. RISC
processors use significantly less chip space as well as other functions such as floating point
arithmetic units and memory management units; these can be placed in the same RISC chip,
reducing space use and power consumption. More parts can thus be placed on the same wafer
chip, resulting in reduced cost of processor chips. RISC processors are far simple, compared
to corresponding CISC processors, and this makes their design quick. This implies their
design can make use of new technological advances when compared to CISC resulting in
bigger performance leaps between processor generations.
Disadvantages
The CISC philosophy has problems; the chip hardware and instruction set for CISC
processors have become more complex with every subsequent computer generation because
it began with generations of processors contained in every new version as a subset. Because it
worked based on the philosophy of storing as many sets of instructions as possible in memory
so that as little space as possible is wasted, they now have the disadvantage of having
different instruction sets taking different amounts of clock time in execution, chiefly because
of having long individual instructions of any length; this slows down machine performance
and operating system performance. The philosophy has many specialized instructions, but
which are not frequently used, and their existence is not justified as operating systems use
just 20% of available instructions. Single codes n CISC are set as an instruction side effect;
setting conditions take time and the code must be examined by programmers before they are
changed by subsequent instructions.
Name, Student Number KF7023 & EN0705 Network and Operating Systems

Name, Student Number 2016/7 KF7023 & EN0705 Network and Operating
Systems
RISC also has its disadvantages; transitioning operating systems fro CISC based architectures
to RISC based architectures has pitfalls. The RISC processor performance depends greatly on
the code it executes, a poor job in instruction scheduling can lead to the processor taking time
to execute, leading to processor stalling. Because of complications in scheduling rules, high
level languages are used more (such as C++), thus leaving instruction scheduling to the
compiler.
Legal and Ethical
Von Neumann’s assumptions on computers has led to the ICT community failing to
understand that there can be problems in the processor architecture that cause risks and
performance issues; fr instance the Intel 80386 and the 80486 processors had floating point
arithmetic bugs. Given that the dominant consideration is performance, concepts such as
safety and control are not given their due considerations. CISC computers have been reduced
to sets for frequent efficient execution and processes necessary for safeguarding the memory
of a processor or OS/ program so other programs such as malware DO not belong to these
extended instructions. This risk is magnified by RISC because it reduces levels of protection
(Berleur and Brunnstein 2001). Further, because of fast development, RISC based computers
which are common are used and with each new faster generation is increased electronic waste
that overloads the environment, according to Balakrishnan, Anand, & Chiya (2016)
Conclusion
Each processor is built with the capability to execute a given set of instructions to perform a
limited set of fundamental operations. Processors have instruction sets that are a bridge
between hardware and software, and their design determines the computer architecture. Two
architectures are used; RISC, and CISC. The main aim of the CISC architecture is the
completion of tasks in as few assembly lines as possible by executing a series of operations.
It has advantages in microprogramming and upward compatibility and uses fewer
instructions for task implementation, an advantage when the main memory is slow. However,
it has limitations because its slower than RISC, complex to construct and they can slow
machine and OS performance due to processing of instruction at different clock speeds. RISC
is another architecture that implements simplified instructions in a single cycle and one of its
advantages is speed, it performs 2 to 4 times better than a comparable RISC computer. CISC
is hardware focused while RISC is software focused, giving RISC a disadvantage of
Name, Student Number KF7023 & EN0705 Network and Operating Systems

Name, Student Number 2016/7 KF7023 & EN0705 Network and Operating
Systems
depending on how the codes it executes are written. There is an ethical issue in that the
transition from CISC to RISK has increased security risks in computers; there is more focus
on performance and protection is not given due attention. Further, because RISC is widely
used, each new generation has high performance that renders previous generations ‘outdated’,
leading to massive e-waste.
Name, Student Number KF7023 & EN0705 Network and Operating Systems

Name, Student Number 2016/7 KF7023 & EN0705 Network and Operating
Systems
Data communications and Encryption technologies for data storage and data
transmission
Abstract
This paper looks at data communications in the modern world and how it has grown as well
as its benefits and disadvantages. Further, the concept of data encryption for data at rest or in
transit is discussed. Data communications has spawned many industries, made the world a
global village, enabled easy and cost effective communication around the world in an instant,
and opened up opportunities. However, data communications has demerits, including risk of
data loss and abuse of such data, such as through hacking for malicious purposes. Data
encryption solves some of the disadvantages and problems of data communications, including
enhancing security for the data, but has its own disadvantages, including risk of data loss
should an encryption key be lost and slowing down system performance. Data
communications and data encryption pose some serious ethical and legal issues. On one hand,
private data must remain safe and secured according to laws in many countries. An ethical
issues arises when a criminal takes advantage of data privacy and protection laws to further
criminal or anti social activity such as terrorism. Another ethical issue is when private data is
breached or used without permission form the owner for commercial purposes, such as
collecting and selling the browser data of a person for commercial gain.
Background
Data communications is the exchange of data between a receiver and a source using
communications and computing technologies ; data communications can be said to be local
when the devices are found in the same geographical area such as one building. The device
transmitting data is the source and the one receiving data is the receiver. The aim of data
communications is both to transfer it (data) and also maintain the data during the
transmission/ exchange process; however data communications does not entail generation of
the data. Digital or electronic data can be moved from one node to another regardless of
where the nodes are geographically located, the contents of the data, or the medium used.
Data communication entails several technologies and techniques whose main objective is t
enable all forms of electronic communication. The technologies include computer
networking, telecommunications, and satellite/ radio communication. Data communications
can only occur if there is a medium for transmitting data between the source and the receiver
Name, Student Number KF7023 & EN0705 Network and Operating Systems

Name, Student Number 2016/7 KF7023 & EN0705 Network and Operating
Systems
(the nodes); of which media can be fiber optic cables, copper, or wireless signals. Most of the
computing today involves data communications; from a computer connected to a Wi-Fi to
sending and receiving e-mails, using a cell phone, and cloud computing, among other forms
of data communications (Sengupta, Kaulgud, & Sharma, 2011). One of the biggest assets
businesses have and among the most important modern day activity is data and data
communications, respectively. Some of the data is highly sensitive, form financial
transactions to private text messages and personal health and financial records that must be
kept safe and secure. In the process of transmission, the data can be exposed to exploitation,
such as hacking by malicious users who can seal personal data such as credit card
information and cause financial losses or even identity theft. Data can be at risk while at rest
(in storage) or in transit (during the process of data communications). Encryption is a concept
in cryptography that involves the process of information/ data encoding in a way that only
people that are authorized (with a decoding code) can access the data. While encrypting data
does not necessarily prevent interference with the data, a would be interceptor is denied
access to the intelligible content (Yu & Cai, 2003). The data or message (plain text) is
encoded through encryption algorithms (which is the cipher) to generate cypher text that can
be read or viewed only when decrypted. encryption entails the use of pseudo random keys for
encryption that an algorithm generates and the intended recipient of the data communication
can then use the provided key for decrypting the data/ message. Encryption is designed to
protect data when at rest (in storage) such as in a database or on a hard drive and when the
data is in transit such as sending data to a cloud storage or sending e-mail. Two main types of
data encryption exist; symmetric key encryption and public key encryption. Symmetric key
encryption (also called private key) entails using a similar key for encryption and decryption;
the source and recipient nodes/ parties must both have and use the same key to achieve
secured communication. Public key encryption, on the other hand, entails the publication of
the encryption key so anyone can use it for encrypting messages, however, only the recipient
node/ party can access the decryption key that allows access to the information (Zhang et al.,
2009). Militaries, governments, corporations, and individuals use encryption for securing data
both when it is a rest and during transit. In data communications, encryption can be used in
whole disk encryption, file or folder encryption, database encryption, multiple user folder
encryption, application level encrypting, e-mail encrypting, and encrypting of Internet/
network traffic.
Advantages
Name, Student Number KF7023 & EN0705 Network and Operating Systems

Name, Student Number 2016/7 KF7023 & EN0705 Network and Operating
Systems
the main advantage of encryption of data in data communications is data security; people and
organizations, including governments send information over media that can be intercepted
and used for malicious purposes. The increased use of the cloud means that people and
entities increasingly surrender the physical control over their data to cloud service providers
where resources, including storage space, is shared. Encryption allows the entities to maintain
control, security, and privacy over their data. Encryption helps organizations and people
move to the cloud and with the keys of the encrypted data, decommissioning provision
becomes very easy. Secure multiple tenancy is achieved in the cloud, courtesy of encryption
and even service providers cannot access one’s data. Encryption also enables entities to
comply with regulations on data security and privacy. Data communications has immense
benefits; some industries today exist solely because of the possibility of data
communications. Technology giants such as Apple, Cisco, Facebook exist solely because of
the possibilities of data communications. The advent of data communications has made it
easy to send messages/ data fast and cost effectively; a TV crew in a remote African region
can quickly relay news to their head office in Europe for broadcasting in a few minutes, and
cost effectively too. Cloud computing, which has immense benefits, is possible courtesy of
data communications. People can collaborate on a global level in a project in real time
because of data communications, while decision making becomes fast and informed due to
data communications (Rajagopalan & Varshney, 2006).
Disadvantages
However, data communications skill has disadvantages; it eliminates or drastically reduces
the face to face communication, and it is not a very good substitute, especially among
humans so social skills are lost. Data communications can be expensive when a new
technology is being installed in a large geographically dispersed organization, such as linking
them with fiber optics. One of the biggest disadvantages in data communications is the risk of
losing privacy and security,or complete data loss. Data remains exposed whether at rest or in
transit, and has led to a whole new criminal industry of hackers and malicious users who
steal/ breach data and sell it or as fr ransom to avoid exposing such data. While encryption
offers several benefits, one of its bigger disadvantages is that it uses keys which implies that
the data security in essence becomes the security of the key (encryption key). If that key is
lost, then the data is effectively lost; this data can be crucial, such as an invention or
classified information. The computational costs associated with data encryption and
Name, Student Number KF7023 & EN0705 Network and Operating Systems

Name, Student Number 2016/7 KF7023 & EN0705 Network and Operating
Systems
decryption can be costly in some applications in data communications, such as cellular
communication. It is also a very complex process that adds administrative tasks to an
organization. Some encryptions, such as full disk encryptions result in reduced system
performance and a poor encryption implementation can give a false sense of security when in
fact, the data is highly exposed to attacks (Rajagopalan & Varshney, 2006)
Legal and Ethical
data communications entails sharing/ sending data such as e-mails; for administrators, there is
the ethical issue of snooping in o this communication or not, especially if the said persons are
suspected of clandestine activities. There is the legal issue f information security, such as
personal information privacy and security acts that various entities must deal with. There is
also the issue of some entities collecting personal information, such as browsing history and
passing off this information to advertisers for commercial gain, without explicitly seeking the
permission of the concerned person. There is also an ethical issue when data is highly
protected and secured, such as using sncryption and various data privacy laws; the
information being exchanged could be by terrorists planning to cause massive harm to
society; should such data be protected?
Conclusion
The present world almost survives and advances due to the possibilities created by data
communications; people ca watch global news, get education, be entertained, and share and
exchange information across the globe in an instant and at very low rates. Data
communication has ed the world to becoming a global village that has brought people,
cultures, countries, closer and closer; a person in Australia can have a real time video chat
with a friend in the United States or Europe. With advances in data communications have
developed risks and disadvantages of data communications, including information abuse,
theft of information, and inspired an entire criminal industry of hackers and malicious
attackers that steal/ breach data for all kinds of purposes, including identity theft. These
disadvantages have led to the development of encryption where algorithms are used to
convert data into unreadable forms while in storage and in transit; providing a first layer of
data protection and security. However, encryption has its demerits; losing an encryption key
means the data is lost; it can slow system performance, and is very costly and complex to
computational resources. Data communications and encryption of data while at rest and in
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Name, Student Number 2016/7 KF7023 & EN0705 Network and Operating
Systems
transit also have various legal and ethical implications. Laws exist on data security and
privacy to which organizations must adhere to. Some entities collect personal information
and sell it off for profit without information the owner of that data.
Name, Student Number KF7023 & EN0705 Network and Operating Systems

Name, Student Number 2016/7 KF7023 & EN0705 Network and Operating
Systems
References
Balakrishnan, R. B., Anand, K., B, & Chiya, A., B. (2016). Electrical and electronic waste: a
global environmental problem. Waste Management & Research. 25, 307-318.
Berleur, J., & Brunnstein, K. (1997). Ethics of computing: Codes, spaces for discussion and
law. London <etc.: Chapman and Hall.
Blem E., Menon J., & Sankaralingam K. (2013). Power struggles: Revisiting the RISC vs.
CISC debate on contemporary ARM and x86 architectures. Proceedings - International
Symposium on High-Performance Computer Architecture. 1-12.
Burger, D., Keckler, S. W., Mckinley, K. S., Dahlin, M., John, L. K., Lin, C., Moore, C. R.,
Burrill, J., Mcdonald, R. G., & Yoder, W. (2004). Scaling to the End of Silicon with
EDGE Architectures. Computer -IEEE Computer Society-. 37, 44-55.
Rajagopalan, R., & Varshney, P., K. (2006). Data aggregation techniques in sensor networks:
A survey. Surface.
Sengupta, S., Kaulgud, V., & Sharma, V. S. (2011). Cloud Computing Security--Trends and
Research Directions. 524-531.
Yu, L., & Cai, L. (2003). Multidimensional data encryption with digital holography. Optics
Communications. 215, 271-284.
Zhang Y.-P., Liu W., Nie X., Cao S.-P., Zhai Z.-J., & Dai W.-D. (2009). Digital image
encryption algorithm based on chaos and improved DES. Conference Proceedings - IEEE
International Conference on Systems, Man and Cybernetics. 474-479.
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Name, Student Number 2016/7 KF7023 & EN0705 Network and Operating Systems
II. Poster
EVALUATION OF OPERATING SYSTEMS AND COMPUTER NETWORKS
Name, Student Number KF7023 & EN0705 Network and Operating Systems
Introduction
The architecture of processors and operating system performance as well as data
communications and encryption technologies were evaluated and discussed.
Brief Discussion
Operating system architecture and performance depends largely on the processor
architecture, which in turn impacts the performance of an entire computing system. The
two processor architectures are RISC and CISC, with distinct advantages and
disadvantages. Growing data communications has benefits and challenges; the benefits
include fast and cost effective communications that has brought the world closer. The
threats include risks to data privacy and security that can be solved through encryption of
data at rest and data in transit
Conclusion
Processor design affect operating system performance; data communication is very
important, but needs better encryption for better security

Name, Student Number 2016/7 KF7023 & EN0705 Network and Operating
Systems
III. Portfolio
OS System Management
Activity The OS had become to me just an everyday screen, much like the picture on a
television set. However, in this practical course seminar, I went deep into the
operating system; I was particularly keen on Ubuntu because I felt it was an
interesting OS that I had very little information about. I undertook various
tasks, including looking at and initiating updates, setting up backups, tweaking
the graphical interface setting and used the command line to make updates and
install programs. I also reviewed the operating system security
Lessons Learned I learned how to install programs and undertake several tasks from the root
terminal in Ubuntu to install .deb files; I also played around with the graphical
interface and settings to improve performance. I was able to use four work
spaces on one computer and set up backups and automatic updates. I was able
to run backup from the root and backed up my data to an external drive using
various commands
Reflection As user interfaces have continued to improve, I was only familiar with the GUI
(graphical user interfaces) and did most tasks from the GUI. However, in this
exercise, I did a lot of experimentation with the command (root terminal) in
Ubuntu, including making a backup and restoring an Operating System in a
given drive. I did a lot of things and I now realize that the GUI is just a screen
covering tons of bare bone code and things that one can do from the root
terminal in the Ubuntu OS; I can now install any program, including from the
web, just using the root terminal
Screen shots
Name, Student Number KF7023 & EN0705 Network and Operating Systems

Name, Student Number 2016/7 KF7023 & EN0705 Network and Operating
Systems
Cisco Router Configuration Tutorial
Activity This task entailed a tutorial on Cisco Router Configuration where a router was
configured in real life using a simulator in GNS3. Commands were used to
give addresses to the routers and the terminal opened with commands used for
configuration. The routers were enabled and given host names using the
host_name command
Lessons I was able to familiarize with the various configuration commands for a
CISCO router, including the no_ip_domain_lookup command so that it did not
have to do a ‘look up’ in case I made a mistake with one of the commands
during configuration. I used configuration commands such as showing the IP
address as an integer using the exec command. I was able to do intersting
things during the configuration, including stopping the routers from timing out
even if I don't go back to it for some time, as well as setting the time out period
when the router logs out after a certain time of no activity. Typing in the
commands gave feedback on configuration just as I had instructed the GNS3
simulator during configuration
Reflection Router configuration to me has always appeared like a very complex thing
especially when configuring actual routers with encryption and passwords for
increased security. This exercise has made it a little bit easy, and with the
practice I got, I am now comfortable configuring Cisco routers, and even
implementing encryption for enhanced security.
Name, Student Number KF7023 & EN0705 Network and Operating Systems

Name, Student Number 2016/7 KF7023 & EN0705 Network and Operating
Systems
Screenshot
Name, Student Number KF7023 & EN0705 Network and Operating Systems