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Pop Quiz: Hexadecimal basics

Whether you're reading a memory dump or just trying to remember the memory address of a PC's COM ports, understanding hexadecimal math can make the task a bit easier. To test your hexadecimal skills, I've created a quick, five-question quiz that tests you on some hex basics.

Whether you're reading a memory dump or just trying to remember the memory address of a PC's COM ports, understanding hexadecimal math can make the task a bit easier. To test your hexadecimal skills, I've created a quick, five-question quiz that tests you on some hex basics.

Note: Unfortunately, our poll tool, which I use to create each pop quiz, doesn't let me indicate a correct answer after each question. To keep from giving away the answers before everyone has a chance to test his/her knowledge, and ruining all the fun, I'm going to hold off posting the answers until next Friday.

About

Bill Detwiler is Managing Editor of TechRepublic and Tech Pro Research and the host of Cracking Open, CNET and TechRepublic's popular online show. Prior to joining TechRepublic in 2000, Bill was an IT manager, database administrator, and desktop supp...

65 comments
IBM5081
IBM5081

Too basic. At least addition and subtraction should be included.

hmplotz
hmplotz

What kind of deal is this? If you are going to post a Quiz, at least invest in some software that is suitable.

bobalbed
bobalbed

well that took me back but do you remember octal the first machine i programed by paper tape on a teletype one k took over twenty min to enter!

cmiller5400
cmiller5400

That was a major flashback of about 10 years ago when I took assembly language in college.

DT2
DT2

Actually, besides having the ability to display large numbers in small spaces, HEX is used because it maps much better to the binary system that computers use than decimal. A nibble is a single HEX character and a byte is two. Makes it easy to convert a number to bits. Had to use a calculator to convert DEAD to decimal but can work out that it is 1101111010101101 in my head.

DixieM
DixieM

SCARY that I still remember this

dontcallmechief
dontcallmechief

I dont know why all of you think Hex is so outdated and is no longer taught. I have only been learning about computers for 2 years and learned about hex a year ago. I got them all right by the way. I think all of you must be old timers since none of you have heard of ipv6.

czarbob
czarbob

My first computer was a Bendix G-15 and its hex coding was 0-9+u-z! Vacuum tubes, wired or functions, diode nand gates and a massive magnetic drum. No hardware registers, they were on the drum! Gotta love that 1950's hardware.

dalexnagy
dalexnagy

This was so easy!!! I started my IT career as a mainframe systems programmer reading dump and doing hex math in my head (for small things....I still have the calculator I bought decades ago to do the heavy lifting hex math). Thanks!

Funker
Funker

It's been awhile but I was still able to do the calculations in my head. It just took a lot longer than it used to. I love it when the answer to one question on the test is found in another.

pcbrooks
pcbrooks

OK. Now test us on octal :)

Tony Hopkinson
Tony Hopkinson

Should have started with binary anyway, without it you'll never get hex.

Info Dave
Info Dave

Back in my day... Yes, I'm an old fart. When I was in school, I could do hexadecimal arithmetic in my head. And that prepared me for reading memory dumps, which I got pretty good at. Fortunately, for productivity reasons, we have gotten away from assembler for development. I'm not one to cling to the passed, but some things should not be forgotten. BTW, I aced the test.

normhaga
normhaga

Yes, hex is still used, taught, and useful.

mjd420nova
mjd420nova

Really old stuff and probably way over the head of most but old time programers. I know they don't teach this stuff in school and only encountered them in tech books for basic programming courses and technical books for electronics people.

dawgit
dawgit

...So, what are the correct answers? I only see how people 'Voted'. I wish that system had been in place on my last math test. :p -d

ljpat
ljpat

It's so easy for those of us who have eight fingers on each hand.

The Altruist
The Altruist

The winner gets a cookie. I guess we'll have to share.

dawgit
dawgit

Just how did you arrive at that figure? The last I looked (which was today) IPv6 is being devoloped by those "Oldtimers" you're talking of. tsk-tsk, you young wipper-snapers think you invented everything. gesh -d

softy.123
softy.123

What makes you think that all of us old timers haven't heard of IPv6? But then, how relevant is IPv6? How many people here are working with it? (I'd actually be interested to know that)

jgw321
jgw321

Gosh some machine that. It makes the Leo II that I worked on look quite primative, as it only used binary (although it did have mercury delay lines). I didn't come across hex until many years after that, when IBM finally managed to catch up and move from punched cards to real computers. To have come up with hex well before the boys in blue, but not be recognised today! Such is the power of marketing. IBM made pretty poor machines (compared with the others), but they knew how to sell. JG

pepoluan
pepoluan

I shiver to think of how aged you are now...   ;) j/k    

NickNielsen
NickNielsen

I could never understand why my students didn't take my suggestion to read every question on the test before answering the first. Only a very few students came to understand that, due to the inter-relationship of electronic terms and quantities, I had no choice but to write exam questions that answered other exam questions.

softy.123
softy.123

Having spent many a time figuring out problems in primitive digital logic circuits back in the old days, I also was waiting to hear someone mention octal. And while we're at it, how about a quiz on reading paper tapes by the hole patterns? Baudot codes anyone?

Muad Dib
Muad Dib

It is just a personal preference but I always found Octal more useful/easier for debugging assembler (if the magnitude of the numbers/word size was relatively small - i.e. 16 bit words).

pepoluan
pepoluan

I too aced the test.   I think.   :D    

CyberGuy
CyberGuy

The teacher has not returned the tests. Until you have yours back, you don't know that you aced it, unless you cheated and stole a copy of the test and answer key ahead of time. I'm not only a IT professional, I'm a licensed educator/education administrator. If you cheated, you will lose your computer privileges for one week for this first offense.

pepoluan
pepoluan

Well, to you it *might* be old-stuff.   But you have to brush-up your hexadecimal abilities for IPv6 addresses, which are written in -- ta da! -- hexadecimal.    

DanLM
DanLM

And not necessarily written by MS have hex numbers in them? To track down in memory what happened(command and values of variables). I would be very supprized if these people don't know how to read a dump. [edited to add] And yes, I know what my first post says... I was at work, and wasn't really paying attention. Dan

NickNielsen
NickNielsen

Project Lead the Way (http://www.pltw.org/Engineering/engineering.cfm) provides an engineering curriculum designed to introduce hgh school and middles school students to the basics of engineering. I taught digital electronics for this program. The single hardest thing was getting the kids to understand that computers don't use base 10.

unskinnybob
unskinnybob

I've always loved the geeky riddle "if you and dead people can read hex, how many people can read hex?"

Bill Detwiler
Bill Detwiler

Just like college right?! Honestly, I wish I could reveal the "correct" answers after each question. But alas, our current poll tool does not allow me to do so. I contemplated several methods of delivering the answers--discussion thread after the quiz, post immediately following the quiz, carrier pigeon, and so forth. Ultimately, I decided to post a thorough explanation of the answers one week after the quiz if first published. Unlike your cranky, old Calculus professor, I'm open to suggestions on changing this format--within the confines of our blogging platform. If you have another idea, let me know!

dawgit
dawgit

I've been wondering the same as you softy. Just when it seems everyone is in agreement, or has an understanding of IPv6, There is another 'conference' on it's implimentation. I guess a 'State of Confusion" exists in everything nowdays. It must be the new 'Norm'. -d edited to add: Overhere it seems to be at least in the thousands. -d

wb4alm
wb4alm

And if you knew just where to "stomp" your foot on a raised floor - you eliminated the need to know how to read a dump... ...but you did get to restart from the beginning!

NickNielsen
NickNielsen

[pre] ------- . . . .. . . . . . . ------- [/pre] . . . . LTRS NO CRLF Edit: and yes, it's been so long I had to look the letters up. Control codes are forever. B-)

wb4alm
wb4alm

Except when you had to work with "split Octal values" on 16-bit words

Tony Hopkinson
Tony Hopkinson

with it, once someone came up with hex, octal was dead in my opinion.

techguru
techguru

if you are in IT and don't know hexadecimal and binary then i suggest you change jobs, this is kindergarden stuff people

dawgit
dawgit

How is someone supposed to do their home work? (with-out Goober and Tweki-weekie ;) ) -d

boyd.w.hudgens
boyd.w.hudgens

There are only 10 types of people. Those who understand binary and those who don't.

AC2
AC2

DEAD hex = 57005 dec So, if you and 57005 can read hex, I believe that would be 57006. BTW - There are only 10 types of people, those who understand binary and those who don't.

seanferd
seanferd

I take it that is 0xDEAD, not "dead". Amusing. English to Hex.

dawgit
dawgit

Now how could I have forgotten. -d

dawgit
dawgit

I can wait. Thanks for the reply to that BTW. I probably blew it though, I just haven't been thinking in a hexadecual manor lately. -d

jgw321
jgw321

For those of us who used hex (and binary - I know the decimal equivalents of the binary powers up to 2^32, and convert most 16 bit binary numbers to decimal in my head) throughout our working lives, this was a trivial quiz. We don't need someone to give us the answers, we need harder questions. You would not expect an A-level English student to wait for the results to see if he spelt CAT right.

jgw321
jgw321

If you AND 1 with anything it will pick off the junior binary digit, 0 if the other number is even, 1 if it is odd. In the case of DEAD it is odd, so the answer is one. I.E. 1 AND 1 equals 1 :) JG

AC2
AC2

As for Boolean not mapping well to the real world, I am not sure that truer words have ever been spoken. Real World Question: Should we cut the red or black wire. Boolean Answer Yes!

DT2
DT2

If you are using a logical AND wouldn't it be two? You and one of the others. But (and this is the tricky part) which one?! Not sure Boolean logic maps to the real world very well.

jgw321
jgw321

So that's just the one then. :)

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