Cumulative 48-hour Computer Trivia

[Serutan]

What I was looking for was a FORTRAN DO loop syntax
error. The compilers of that time didn't abort on a syntax
error, so the code built and went to Venus with bad results.
Can't happen now, since I am not aware of any compiler
that does not abort a build on a syntax error.

Cartouch Bee came closest, so it's his turn now.

 

[starlifter]

Do you know what version of Fortran that was, specifically? Was it Fortran77, or was it an earlier one? I began programming in Fortran in 1979, and am curious. I have used it in autonomous aerospace vehicle navigation systems, but I have not had a role in spacecraft software of any sort.

 

[Cartouche Bee]

Hi,

Sorry I have not been able to get access to the site due to DNS server problems with the recent changes with telefragged servers. Even though Serutan passed, this on to me I may not be able to get access again, so Serutan, please take another go, I'm pretty sure you will make a better question than I would. Besides, I don't think I hit the mark on the question.

As for the FORTRAN version, I'm pretty sure that back then, that with programming by punch cards that it was a lot of trial and error/testing. ( I guess this error was not caught! Might have actually been a hardware error though in this case but I don't have any facts to substantiate the claim.) Definitely had no precomplier to help in debugging (Some systems produce Punched tape from the cards but I'm sure that was not the process on this system.). Oh, I've did some programming of FORTRAN on punch cards so it is not really a guess cause even in later years this sort of thing was happening and precompilers were implemented to reduce codeing errors.

CB

 

[starlifter]

How I do remember the days of punch card programs, and batch runs on the IBM 360 and Vax 11/780. After thinking about it like I should have, I'm sure the problem was not in the Fortran spec, but completely a compiler issue. Ours would reject on pass#1 based on syntax errors, so I never had experience with compilers that allowed faulty code to execute. APL would do that, but it was an interpreted interactive language.... but when it hit a bad syntax, even that would be identified and execution halted. It boggles my mind that at least a two-pass compiler did not process all code, even if the testers did not do their job and generate test cases to exercise all sections, no matter how obscure, of the source code.

 

[Pliny The Elder]

I actually understood some of that! Lol, I hope to be able grok all that stuff, one of these days...when I grow up

 

[Serutan]

Originally posted by starlifter
How I do remember the days of punch card programs, and batch runs on the IBM 360 and Vax 11/780. After thinking about it like I should have, I'm sure the problem was not in the Fortran spec, but completely a compiler issue.

Absolutely. In 1961 (when this S/W would have been written), even Fortran IV was a figment of the imagination. Also,
compilers had only existed for 5 or so years at this time...
I suspect (but cannot cite evidence) that this probably helped
trigger development of the multpass compiler.

 

[starlifter]

Well, no activity for more than 48 hours, so I'll ask a question.

Name a stable MS operating system. No wait. Both and oxymoron "Operating System" & MS, and reference to the word "stable".


OK, hmmmm. Let's see.

Hard drives. What is the difference in a "primary" hard drive and a "secondary", with regard to the BIOS in a PC?

And what is the difference in a "master" and a "slave"? In regards to hard drives. Computer hard disk drives, that is.

 

[Lucky]

Hmm, not sure how much info you want!

Primary: The drive, usually assigned to the letter C: by the BIOS, where it will look for an operating system. Newer BIOS software allows choosing a specific drive though.
Secondary: Well, the drive the BIOS will not look for an OS. Again, a newer BIOS may be able to select several harddisks to look for an OS.

Master: The drive that has the primary connection to the IDE bus. Must be installed for that specific IDE connection to be activated.
Slave: Can only be plugged in when a master is present on that IDE connection.

Master/Slave is for IDE bus systems, but not for example for SCSI drives.

 

[starlifter]

Pretty close. Good enough so you get the next question, Lucky .


But here is what I was talking about... The Primary channel is the INT 14 (interrupts are assignable, but the convention is INT 14) for the primary, in BIOS. The Primary can have a Master and Slave IDE device attached to the same interrupt.

The Secondary channel (INT 15, by default) also can have a master and secondary device attached, giving a total 4 IDE devices on an average system.

The devices are usually hard drives, but CD ROMS, CD RWs and even lots of less-common devices like the Zip drive can hook up, though each device must be set as master or slave.


You can also add extra cards, with tertiary and quadrenary (3rd and 4th) IDE channels, each supporting another master and slave.

If you want more than 4 total IDE devices (e.g, hard drives, CD ROM/RWs, Zips, etc.), then you need to cough up more interrupts, and (unless you have a special motherboard) need to add a $40 IDE card.

Your question, Lucky!

 

[Lucky]

Sorry about the delay, I might get a few serious flooding problems the next days, so that is a real concern right now.

Oh and starlifter, I thought we shouldn´t be that technical.

Question:
What is the common max. length of the following cable types?
USB -
10BaseT (10Mbit ethernet, twisted pair, Cat5) -
100BaseT -
Firewire (IEEE-1394) -
SCSI -
Ultra SCSI, Wide SCSI, UW-SCSI -
Ultra2 SCSI, U2W-SCSI, Ultra3 SCSI -
RS232 (serial port, 9600baud) -

For all cables just the most basic industry standard.

 

[starlifter]

Sorry about the delay, I might get a few serious flooding problems the next days, so that is a real concern right now.

Oh and starlifter, I thought we shouldn´t be that technical.

Hope you have a boat or some golashes! The answer just sounded techincal... it is just the very basic, but confusing, way that IDE ATAPI drives work (e.g, 4 on most machines.. 2 on each interrupt, a master & slave, and a Primary... these determine the drive lettering that some people have discussed in other posts lately, and should be understood by people adding a new hard drive, as some have recently posted).

About the question, I'll wait a day or two to give someone else a chance, since I already know most of those quite well .

 

[gonzo_for_civ]

Ahh.. Glad to see this thread get moving again. I was a few days from unstickying it. As for the question, I have no idea!

And good luck with the flooding Lucky!

 

[Lucky]

Yeah, now if somebody would just try to answer!

Come on people, this is the thread where you can search ( ) for the answers.

 

[starlifter]

I already knew this stuff, but wanted to give others a chance. If some types of questions we ask don't get responses, we can always ask more lively sorts of questions. But this one is excellent, though obviously (from no replies) kinda dull to most people (not dull to me, as my machines don't work right if cables are not properly sized and routed!).


by Lucky:

What is the common max. length of the following cable types?


My answers will assume single cables, not enroute signal enhancers that can extend range dramatically, like USB up to about 80 ft. This is a good reference document for people that don't know about computer cabling... great question Lucky, and it is very useful for people, too!!





SCSI

The SCSI question are trick (I use SCSI a lot, even to write this!). Cable length is not a function of those terms, as phrased.

Ultra = 50 pin cable (assuming internal) (8-bit devices)
Ultra Wide = 68 pin cable (16-bit devices)
Ultra2 SCSI, U2W-SCSI, Ultra3 SCSI - LVD

SCSI Cable Length is a function of transmission method (the send/acknowledge turnaround), and waveform. The faster (in MHz) the signal, the shorter the cable.

These are total cable lengths, from adapter to device (or device to device if adapter in middle):

Non-Fast devices (basically SCSI-1, 5MHz): 6 meters (19.7 feet)
Fast devices (e.g., SCSI-2, 10MHz) - 3 m, 9.8 feet)
Ultra (20MHz) - 1.5m (4.9 ft)
LVD devices (e.g., U2W) - 12m (39.4ft) , but can change, based on characteristic line impedence.

EXTRA CREDIT:
Any SCSI Differential device = 27m (88ft) ... but conservatively used at 25m (82ft).


OTHER

USB - Trick question (more than one std answer)- Full speed (12 mbps) = 3 meters (16 feet); 1.5 mbps = 3m.
10BaseT (10Mbit ethernet, twisted pair, Cat5) - 100 meters
100BaseT - 100 meters
Firewire (IEEE-1394) - Trick question (depends on cable type). Common 28 AWG = 4.5 meters, but 24 AWG = 10m, and Optical = 700m.
RS232 (old, slow serial port: 9600baud) - 15 m, 50 ft.

EXTRA CREDIT...

RS232 (Normal Serial, DTE: 64,0000 bits/s) - 3 m, 10 ft.
Parallel Cable (Old Centronics) - 15 feet (9 is safer!)
Parallel Cable (IEEE-1284) - 30 feet in length (go short for data reliability!)




LOL, you should see the wiring jobs I do with computer stuff... I almost always use the full limits of everything, except Optical, that you mentioned above .

 

[Lucky]

Hmm, not quite, but very good nonetheless.

USB 12mbps should be 5m.

The rest is more or less correct, go on!

 

[starlifter]

Ah, you're right, Lucky! I typed 3m twice .

OK, with all the avatar creating and editing by CFC members lately, here is a timely one. It is multi-part, but pretty easy.

What is advantages & disadvanatages to using the following formats for an avatar: JPEG, GIF, BMP, TIFF PSD. Also, which are lossless and which are lossy? Which is generally best for graphics & cartoons? Which is generally best for natural life? Which can have transparant background?

And one more part: you must also list at least 5 downloadable graphics editing programs, rank them, give your short opinion (1 or 2 lines) on each, and provide their URLs.


---> Remember, this 48-hour thread allows you to research and use anything to help you out (even other people)!

 

[King of Camelot]

I'll give this a try first without research....that comes when I know I'm wrong.

What is advantages & disadvanatages to using the following formats for an avatar: JPEG, GIF, BMP, TIFF PSD

JPEG is very good at cutting down on a picture's file size but is not that good at preserving some details. GIF also cuts down file size but not as much as JPEG, it retains more detail and can have transparency. BMP has several different types which can hold differrent amounts of colors which are: 24-bit Bitmap, 16 color Bitmap, 256 color Bitmap, and Monochrome Bitmap. Generally BMP are large and don't lose color unless you save it in a type that doesn't support that many colors. Don't know about the other two formats there.

Also, which are lossless and which are lossy?

In my experince if you use the right type BMP don't are lossless, GIF are lossy but not much, and JPEG can be pretty lossy at times.

Which is generally best for graphics & cartoons?

Don't Know.

Which is generally best for natural life?

Don't Know, not sure what you are asking here, please specify.

Which can have transparant background?

The GIF can have a transparent background.(Which is why so many avatars are in GIF format!)

For the graphics programs, I'll get back to you on that.

 

[starlifter]

Nice work, King of Camelot! I'll wait a little longer for you to finish. The Natural comment refers to "real life" images, as opposed to typical computer generated, or animated, images.

 

[Pliny The Elder]

I think you have jpeg and gif backwards, there. gifs only support 8-bit color, however, they do support layers, thus they can be transparent, and animated. jpegs are compressed, but can support 24-bit color. bmps are uncompressed, lossless, and are pretty much limited only by hardware. huge files are possible. tiff is another true-color lossless format. i could look the other up, but i'm just answerin off the tippy top of my head. many web graphics are goin ta png, now, it's a highly compressed open algorythim. gif has been been attacked by lawyers, and jpeg has a patent claim pending...

 

[King of Camelot]

Some one else can finish it off, starlifter, because I can't find stuff on TIFF although I have heard of it so I am at a stomp.