Re: Nostalgia/RE: what is Hex?
- From: Jim Dunleavy <jim.dunleavy@xxxxxx>
- To: programmingblind@xxxxxxxxxxxxx
- Date: Fri, 22 Feb 2008 13:04:43 +0000
Hi,
My first experience with VAX Macro32 assembler was writing code
to read magnetic tapes of data which were being migrated from an ICL1900
machine.
The ICL machines had a 24-bit word size and a 6-bit character set.
If that system had won out, we could be measuring word sizes by the
dozen instead of the octet.
--Jim
----- Original Message -----
From: Chris Hofstader <chris.hofstader@xxxxxxxxxxx>
To: <programmingblind@xxxxxxxxxxxxx>
Sent: Friday, February 22, 2008 11:38 AM
Subject: Nostalgia/RE: what is Hex?
> Hi,
>
> Sina's post reminded me of programming on what is now a relic, the NCR
> Criterion which, instead of using twos compliment actually had a separate
> sign bit thus making it a sort of 17 bit processor. We programmed it in a
> strange old language called NEAT/3 which was pretty much an assembly
> language with COBOL extensions. No matter how I tried, I couldn't use
that
> extra bit for anything other than the sign value of a register.
>
> I left that job in 1982 and in the years hence, I have only met one other
> NEAT/3 programmer - Mervin Robertson, the guy who runs Sight and Sound in
> the UK and sells FS, AI and other AT products.
>
> A possibly appocraphal story about Kernigan and Richie is that they put in
a
> request for a DEC 10 for their new OS project which grew up into Unix. A
> DEC 10 is actually a 10 bit based mini and was the machine that Compuserve
> standardized on, which caused horrible problems when they tried to move
into
> the Internet era moving them from the number one online service to going
for
> cheaps at a fire sale. At Bell Labs, K&R had their budget cut and were
> givine a PDP 8, which one might guess by its name, was an 8 bit mini. If
> they had gotten the DEC 10, would we all be using 10 bit ASCII these days?
>
> cdh
>
> -----Original Message-----
> From: programmingblind-bounce@xxxxxxxxxxxxx
> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Sina Bahram
> Sent: Thursday, February 21, 2008 4:58 PM
> To: programmingblind@xxxxxxxxxxxxx
> Subject: RE: what is Hex?
>
> A few things. big endian versus little endian is arbritrary, so it's not
a
> fact with respect to storage.
>
> More importantly, the minimum and maximum of a signed 32 bit integer is
not
> -65535 to 65535, it's actually -32767 to 32767
>
> If it is signed, then it is 0 to 65535
>
> At the end of the day, you only have 2^16 permutations of 16 bits in a
> binary system; thus, you have a maximum of 65536 positions, and so you
have
> half as much capacity if you are using twos complement to allow for both
> negative numbers and the concept of 0.
>
> Hope this helps
>
> Take care,
> Sina
>
> -----Original Message-----
> From: programmingblind-bounce@xxxxxxxxxxxxx
> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of James Panes
> Sent: Thursday, February 21, 2008 2:35 PM
> To: programmingblind@xxxxxxxxxxxxx
> Subject: Re: what is Hex?
>
> Yes, Hexidecimal numbers are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E,
F
> for a total of 16 possible digit values.
>
> As stated before, this is much more convenient for the computer as 16 is
an
> even power of 2 and computers actually use binary, 0 and 1. The
hexidecimal
> representation is actually easier for humans to read than binary.
> Hexidecimal digits are grouped into groups of 2 for a total of 16 x 16 or
> 256 possible values. This is a standard byte. Before unicode, a single
byte
> value was used to represent an alphanumeric character and two bytes or a
> word were used to represent a 32 bit integer with values possible from
> -65535 to 65535. This explains the limit of the size of variables in older
> games.
>
> The original Intel 8086 processor had 16 bit registers. Operations for
> anything larger had to be synthisized with software.
>
> What's more, for integer values larger than 255, the least significant
pair
> of digits is stored first. For example, if you were looking for the value
> 301 (decimal) in a game save file, you would find it represented as 23 01
in
> the save file.
>
> Since this list is about programming and not game save file hacking, I
will
> end my lecture here.
>
> Anyone with further interest in this topic can write me off-list
>
> Regards,
> Jim
> jimpanes@xxxxxxxxx
> jimpanes@xxxxxxxxxxxx
> "Everything is easy when you know how."
>
> ----- Original Message -----
> From: "Valiant (on laptop)" <valiant@xxxxxxxxxxxxx>
> To: <programmingblind@xxxxxxxxxxxxx>
> Sent: Tuesday, February 19, 2008 8:43 AM
> Subject: Re: what is Hex?
>
>
> Hi.
> I didn't see anyone mention this part about hex.
> Hex is just another number scale like the standard one 0 to 9 or the
binary
> one 0 to 1. Hex is 0 to f I think, making it bass 16, where the one we use
> every day 0 to 9 is bass 10 and binary is bass, hmm, someone help? 0 to 1?
> The possible digits in hex are 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, e, f
> can't remember if hex starts with 0. It lets you have larger numbers
without
> taking up as much space. MAC addresses on networking equipment use it.
> some of that could be wrong, it's been two whole years since I had to
study
> that, here.
>
> ----- Original Message -----
> From: "Sina Bahram" <sbahram@xxxxxxxxx>
> To: <programmingblind@xxxxxxxxxxxxx>
> Sent: Monday, February 18, 2008 4:03 PM
> Subject: RE: what is Hex?
>
>
> 21, but yes he is, Thanks Chris
>
> Take care,
> Sina
>
> -----Original Message-----
> From: programmingblind-bounce@xxxxxxxxxxxxx
> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Marlon Brandão
> de Sousa
> Sent: Friday, February 15, 2008 12:12 PM
> To: programmingblind@xxxxxxxxxxxxx
> Subject: Re: what is Hex?
>
> Are you serious about Sina being 22 years old only? Man I have seen people
> who have studied computers for many more than this quantity of years and
> don't seen to know a half of what Sina knows easily ...
> Marlon
>
> 2008/2/15, Chris Hofstader <chris.hofstader@xxxxxxxxxxx>:
> > God Sina, you bring back memories of Z80 and needing to "poke"
> > instructions and data into memory before execution. I would have
> > thought you, who was born in 1986 would never had to get to that
> > level. Personally, I think it's a really valuable exercise even if
> > one never actually needs to use it in a "real" program just to get a
> better understanding of what a processor "sees"
> > and how base 16 numbers can be turned into both instructions and data
> > depending upon how the processor looks at them.
> >
> > In the network edition of "Bank Street Writer" a word processing
> > program written entirely in assembly, that was pretty popular in the
> > years before you learned to talk, I added a function called,
> > "DON'T_CALL_THIS." If you did call it the program would crash as the
> > instructions looked random. If, however, you looked at the last
> > handful of bytes of the program as ASCII, it read "FSMITHISAWORM."
> > Frank Smith, a really great guy, was the client on the gig and we
> > decided to immortalize him in an Easter Egg that only an ubergeek could
> find.
> >
> > Now, just for shits and giggles, try to reconstruct the function in
> > 80x86 assembly and receive the truly wasted chunk of time award.
> >
> > cdh
> >
> > -----Original Message-----
> > From: programmingblind-bounce@xxxxxxxxxxxxx
> > [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Sina
> > Bahram
> > Sent: Thursday, February 14, 2008 9:28 PM
> > To: programmingblind@xxxxxxxxxxxxx
> > Subject: RE: what is Hex?
> >
> > *smile*, wlel actually, if you really want to get down to it ... it can
> be.
> >
> > Assembler compiles down to executable instructions to the processor,
> > which are most often and most easily read in hex.
> >
> > I used to know almost all of the 8086 instructions and some of their
> > hex equivalents a while back. It's really useful when analysing
> > exploit and virus code.
> >
> > Take care,
> > Sina
> >
> >
> >
> > -----Original Message-----
> > From: programmingblind-bounce@xxxxxxxxxxxxx
> > [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Alex Hall
> > Sent: Thursday, February 14, 2008 8:47 PM
> > To: programmingblind@xxxxxxxxxxxxx
> > Subject: re: what is Hex?
> >
> > Right, but it almost sounds like some sort of programming language.
> >
> > Have a great day,
> > Alex
> >
> > > ----- Original Message -----
> > >From: Joseph Lee <joseph.lee22590@xxxxxxxxxxxx
> > >To: programmingblind@xxxxxxxxxxxxx
> > >Date sent: Thu, 14 Feb 2008 17:27:12 -0800
> > >Subject: re: what is Hex?
> >
> > >Hi Alex,
> > >It's a shortened form of hexadecimal.
> > >Cheers,
> > >Joseph
> >
> > >> ----- Original Message -----
> > >>From: Alex Hall <mehgcap@xxxxxxx
> > >>To: programmingblind@xxxxxxxxxxxxx
> > >>Date sent: Thu, 14 Feb 2008 20:18:21 -0500
> > >>Subject: what is Hex?
> >
> > >>Hi all
> > >>Whatis this Hex that has been talked about
> > >recently?
> >
> > >>Have a great day,
> > >>Alex
> > >>__________
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>
>
> --
> When you say "I wrote a program that crashed Windows," people just stare
at
> you blankly and say "Hey, I got those with the system, for free."
> Linus Torvalds
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