APCSP Exam Unit 1

Which of the following lists the numbers in order from least to greatest?

01010 1110 010000

What is the 4-bit binary number for the decimal number Ten (10)?

1010

Two students have developed a protocol in which they send 4-bit messages to each other. They decide to modify their protocol to start sending 8-bit messages instead. How many more values can be represented in an 8-bit message than a 4-bit message?

24 = 16 times as many values

The world is currently in a transition to using IPv6, a newer version of the IP protocol that uses 128-bit addresses instead of 32-bit addresses used by IPv4. What is the main problem that IPv6 was created to solve?

32-bit addresses could not ensure that every internet-connected device can receive a unique IP address

What is the minimum number of bits you would need to encode the 26 letters of the alphabet plus a space - a total of 27 characters?

5 bits

8 bits is enough to represent 256 different numbers. How many total bits do you need to represent 512 (twice as many) numbers?

9 bits

The Internet Engineering Task Force (IETF) defines the protocols and standards for how the Internet works. The members of the IETF are:

A loosely organized collection of citizens and engineers.

Which of the following statements are true about routers and routing on the Internet. Choose two answers

A packet traveling between two computers on the Internet may be rerouted many times along the way or even lost or "dropped". Routers act independently and route packets as they see fit.

ASCII characters can also be represented by binary numbers. According to ASCII character encoding, which of the following letters is represented by the 8-bit binary value: 0100 0010

ASCII Character: B

A middle school is expanding to open a high school next year, doubling the total number of students. The school keeps a database in which each student's unique ID number is stored as an 8 bit number called studentID. Before the arrival of the new students almost every 8 bit number has already been assigned to a student. Of the options provided below, which is the smallest change to the way studentID is represented necessary to ensure each incoming student receives a unique ID?

Add a bit to studentID to double the number of IDs that the database can represent

Computer A sends a packet intended to reach computer F. Along its path it arrives at Computer C. Which computer should Computer C forward the packet to in order to use the most cost effective path?

Computer D

The various protocols in use on the internet are said to operate in layers in which the protocol(s) at each layer solve one problem related to networked communication, and higher layers are built on top of, and rely on, the lower layers to do their jobs. From the list provided choose the two (2) answers that correctly describe which internet protocol relies on the other. For example: if protocol A relies on protocol B, it means that A is a higher level protocol than B, and thus protocol B must exist and work properly in order for protocol A to do its job. Select two answers.

HTTP relies on TCP/IP DNS relies on TCP/IP

How does a computer resolve a domain name into an IP address?

It asks a DNS server for the corresponding IP address

What is the best explanation for why digital data is represented in computers in binary?

It's easier, cheaper, and more reliable to build machines and devices that only have to distinguish between binary states.

A user clicks on a website, and it begins to load immediately, but it takes a long time to load completely and pictures appear slowly, one by one. Which of the following is demonstrated through this situation?

Low bandwidth, low latency

Which of the following BEST describes how protocols on the Internet (e.g. IP, TCP, HTTP) make use of abstraction to accomplish their respective purposes?

Low level protocols can provide functionality to high level protocols without revealing the details of how this is accomplished.

Which of the following is NOT true about TCP/IP packets?

TCP guarantees that no packets are ever dropped

Number systems with different bases such as binary (base-2), octal (base-8), decimal (base-10), and hexadecimal (base-16), are all used to view and represent digital data. Which of the following is NOT true about representing digital data?

When data is large enough computers switch to using decimal representation instead of binary, because you can represent larger numbers with fewer digits.

Which of the following is MOST likely to be answerable using all the data collected by this monitoring?

Which websites are most frequently visited before and after school hours from a school computer

According to the domain name system (DNS), which of the following is a subdomain of the domain example.com?

about.example.com