Dell Interview - Help!!!

[BuddMan]

http://www.millbury.k12.ma.us/~hs/techrepair/7irqquiz.html

Ok, need help with this as I know they will be asking me questions on that as well. Anyone got any ideas. And Tempest, thanks for the quick response.

EDIT: Why is NT 4.0 not plug and play? I need to know the answer to this as well (was asked this in the 1st interview and didn't know the answer).

Double Edit: I know some of the answers on that link, like IRQ stands for Interupt Request (right?), DMA=Direct Memory Access, and I/O stands for In/Out. But beyond that I'm a little confused.

[seether]

Buddman, sorry for the length - I just copied a section from an old book of mine.


here's a relevant ms kb article number for you to check out regarding plug and play....... Q156344

It's been over a year since I've had to deal with any of this stuff, so if noone answers your questions by the time I dig more detailed answers up, I'll post it or email it to you. I did home user tech support for gateway and nt tech support for compaq for awhile and 99% of this stuff never comes up. If you're supporting nt in the business, it would be a good idea to get real familiar with regedit and regedt32 (specifically, when/why to use each, and how the differ) and make sure you're comfortable working with domains.

and check out Microsoft's website - their support pages, knowledge base, and MSDN will be one of your best friends.

IRQs, DMAs, and I/O Addresses


In order to ensure that information is passed between the system modules and the CPU in a timely fashion, devices must be able to directly communicate with the CPU. Because the processor is a busy device, system components must first get the CPU’s attention. This is accomplished through a special set of lines, called interrupt request lines (IRQs), in the bus. IRQs are given a number, ranging from 0 through 15, to identify them. In turn, devices are given an IRQ to use. However, with most BIOSs, no two devices in the computer can use the same IRQ or else the processor won’t know who is calling it. Some of the newer BIOSs support IRQ sharing, but you need to consult with the vendor’s documentation to see if this feature is supported.

Once the CPU receives an IRQ from a device, it can directly communicate with that device through I/O addresses, also known as I/O ports. I/O ports are assigned a range of numbers which are in turn assigned to specific devices. As with IRQs, no two devices can use the same I/O address.

There are times when some components needs to write information directly into main memory. When a device has to do this, it uses a channel called a Dynamic Memory Access (DMA) Channel, to do so. This method can be used to improve the module’s performance, as you are basically removing the overhead of having the processor move the information from the device to main memory.

Standard IRQ Settings


The computer industry has come up with a set of standard IRQ settings. These settings should be used whenever you are installing a device. Table 1-1 lists the standard IRQ settings.

IRQ Number Standard Device Assignment
NMI (nonmaskable interrupt) Memory parity error
0 System timer
1 Keyboard
2 On motherboard, cascaded from IRQs 8-15
From device IRQ2, is re-directed to IRQ9

3 Serial port (COM2)
4 Serial port (COM1)
5 Parallel port (LPT2)
6 Floppy controller
7 Parallel port (LPT1)
8 Real-time clock
9 Unassigned (also redirected from IRQ2)
10 Unassigned
11 Unassigned
12 Mouse
13 Math co-processor
14 Hard disk controller
15 Secondary hard disk controller



Table 1: Standard IRQ Settings

IRQ 2 is the subject of a good bit of confusion. This results from the fact that the original PC had only 8 interrupt lines, numbered 0 to 7. When the AT was designed, a second interrupt controller was added to provide 8 more interrupt lines (numbered 8 to 15). This second interrupt controller had to deliver its signal through the primary controller on the motherboard, and IRQ 2 was chosen for this task (‘cascade’ from second controller). Unfortunately, some earlier cards had already made plans to hook into the IRQ 2 signal wire, so on newer machines with the second controller, that signal wire now leads to IRQ 9 on the second controller. The bottom line: For hardware purposes, IRQ 2 and IRQ 9 should be considered the same interrupt signal, and should not be used together in the same system.



Exam Watch: Know your IRQs cold. There are several questions on interrupt assignments on the exam.

Standard I/O Address Settings


In addition to standard IRQ settings, you need to know the standard I/O address settings. Table 1-2 lists the more frequently used port addresses.

Port Address (hex range) Device
1F0-1F8 Hard drive controller, 16-bit ISA
200-20F Game control
201 Game I/O
278-27F Parallel port (LPT2)
2F8-2FF Serial port (COM2)
320-32F Hard drive controller, 8-bit ISA
378-37F Parallel port (LPT1)
3B0-3BF Monochrome graphics adapter
3D0-3DF Color graphics adapter
3F0-3F7 Floppy controller
3F8-3FF Serial port (COM1)

[ZokesPro]

On Dell systems, you cannot change the IRQ setting in the bios.
BTW, I sent you an email BuddMan, hope it all helps. Also if you can speak another language you'll be almost garanteed to have and KEEP a job there with a language premium tacked to your pay check.

[BuddMan]

Thanks again guys. Yeah, I know most of this won't come up in the actual job. It's the interview that I'm worried about. If they are gonna ask me questions for an hour, well, that's a lot of time to find out what I know and don't know, and I pretty much want to impress these people. Zokes, am about to read your email. Thanks again everyone.

[ALBPM]

Just be upbeat, positive and don't show any signs of getting fustrated by their questions. I think they are more interested in your people/teamwork skills than the technical stuff. DELL probably will give you lots of training on the technical part. But you have to show them you can work/help the worst of the gene pool without getting impatient or fustrated.

Back when I was a total NOOB and owned a couple DELL systems their Customer Support people were cool. They would actually spend the time to help you upgrade your DELL system wether you got the parts from them or not.

"Your system is fine..... It's the interface between the keyboard and chair that's causing the problems"

Paul

[BuddMan]

Ok, another question (I'll probably have plenty before the day is out). What is the math-co processor on IRQ 13?

[GT98]

Originally posted by BuddMan
Ok, another question (I'll probably have plenty before the day is out). What is the math-co processor on IRQ 13?

That was back in the day of the 386/486 when there was an additional addon chip that did the FPU caluations.

[BuddMan]

You mean floating point calculations?? So it isn't used anymore? Does that mean IRQ 13 is now open?

[az]

I don't think that's important for the job, but I think it is what's included in the CPU since the 468DX (what differentiated it from the 486SX), and what was before an add-on option: The arithmetical co-processor, doing just as the name suggests. I believe it's there for faster floating-point computations, but I don't really know

And I really don't think they'll ask you that (why should they? Never heard of ANY problems with this. It's like someone has problems with his MMX unit in his CPU).

AZ

[az]

Oh, I see GT beat me to it

I believe it still uses IRQ 13, for backwards compatibility, and because of the history, how it got to be an on-chip part of the CPU rather than an extra chip.

AZ

[{PainCresT}DAn]

$13.25 USD is about @19.50 CND and that's better than I make and I've been a Network Admin for about 3 years now and also helpdesk tech for Sympatico and EDS for 2 years so I'd say thats not bad...BTW I make $18.25 CND which is about 40K CND. Hope ya get it... not bad at all for a college student.

[{PainCresT}DAn]

I remember putting a Math-co in my 386 DX40... it make wolfenstein work much better and allow me to even run AutoCAD 1.0 LOL before that I used a TSR that emulated Mathco... LOL those where the days LOL

system spec @ the time:
386 DX40
Dont remember the mobo (I was a newbie)
2MB Ram
512K SuperVGA trident (was totaly awsome at the time... it was SUPER VGA!!!!)
120MB HDD
200W PSU
14" AAMAZING Monitor
Goldstar keyboard
and a bad ass 2400Baud modem
LOL
LOL
LOL

[az]

Wasn't it an SX then?

AZ

[SpiralDragon]

Originally posted by The PIT


Wasn't it Dell that sold twin processor units with windoze 98 installed???

AFAIK it was alian ware not dell ... got one hell of kick when i saw that ... especialy since it was my best freind who referd me and recomended it for me ..... and he is realy tech savy....

[SpiralDragon]

BTW.... concerning MAC PCs.... do they use IRQ, DMAs and I/O ports as well ... in comparison to X86 systems that is....