Monitor

Chadae

Hi everyone.

Does the A+ testing concentrate at all on Monitors?? Such as the screen resolutions and video color depths? I thnk im overstudying this section.

Webmaster

Definitely part of A+ core, but it may not end up in 'your' exam.

Take a look at www.techexams.net/technotes/display.shtml , besides most of the required info you need to know it lists the related exam objective as published by CompTIA at the bottom of the page.

(please post A+ related questions in the appropriate A+ forum, no need to repost, I've moved your post already )

Sartan

All you need to know:
All resolutions are definately in powers of 2 and powers of 3, so you can easily find out if a resolution is invalid (although you can't configure an invalid resolution)
1-bit color=monochrome=2 colors (b&w)
4-bit color=yuck=4 colors (CGYB)
8-bit color=blah=256 colors
16-bit color=high color=65535 colors
32-bit color=true color=16776216 colors

copied from technotes here
Video Mode Resolution and Color Depth
CGA 320 x 200 with 4 colors
640 x 200 with 2 colors
EGA 640 x 350 with 16 colors from a palette of 64 colors (text mode)
640 x 200 with 2 colors (graphics mode)
VGA 640 x 480
SVGA 640 x 480, 800 x 600, 1024x 768 and higher with X colors from a palette of 16.7 million color.
(X depends on the amount of video ram, ranges from 256 - 16.7 million)
VRAM

VRAM or Video RAM is dual ported (it can be read to and written from at the same time). Although VRAM is fast, it is not as fast as WRAM.


WRAM

WRAM or Windows Accelerator Card RAM is faster than VRAM, and thus produces better video than VRAM. WRAM is also dual ported, meaning it can be both read from and written to at the same time.


SGRAM

SGRAM or Synchronous Graphic RAM synchronizes with the CPU bus. SGRAM uses masked writes and blocked writes in order to increase bandwidth for intensive graphics. SGRAM is not dual ported, and cannot be read to and written from at the same time, although it can open two memory pages at once.

Refresh rates:
60, 62, 65, 70, 72, 75, 80, 85, 90, etc...
Doublescan is when a refresh rate is doubled for low resolutions, like 320x200 ~ 120Hz = 60Hz*2
Interlacing is when it draws one line, skips the next, and when it reaches the bottom, it draws upwards and draws the skipped lines.
Antialiasing redraws jagged lines to make them appear smooth by color blending.
Antistropic filtering pre-loads textures and sharpens them.
Mip mapping pre-loads different textures for distances (low quality for far away)

If a monitor doesn't turn on or is all black, in order:
Check if it's on
Check the power plug
Check the VGA plug
Check the brightness/contrast
Boot to safe mode/vga only mode.
Check the screen settings in the Display control panel.
Fix if neccessary.
Check drivers... etc..
Reboot, check the bios (if you can) to make sure AGP/PCI/Onboard is booting first, whichever you have.
Check if the video card is loose..
Replace the video card (FRU ~ field replacable unit)

CRT=Cathode Ray Tube.

LCD stands for Liquid Crystal Display.
TFT stands for thin film transistor.
TFT Active matrix LCD = Pretty.
Passive Matrix = not so pretty, but viewable better at angles.
LCD monitors don't require refresh rates, it's just for compatibility with programs.
LCD's look best at a 4:3 ratio.

When repairing monitors, *FOR GOD SAKES* do not use an antistatic wrist strap, it could kill you.

A GPU is a dedicated CPU for graphics processing - Graphics Processing Unit
AGP - Advanced Graphics Port - Allows asynchronous RAM/CPU processes that don't rely on the PCI System clock. (Thats why GeForces are so darned fast, they run at 350Mhz!)
AGP runs at 1x, 2x, 4x, 8x. Each is faster than the next, numbers are specific per card.
The AGP bus is connected to the northbridge on a motherboard.

A few video "standards"
OpenGL - Cross-platform 3D Effects - Front-end to HAL
3dfx - Voodoo based cards 3D effects ~ Cross platform - Front-end to HAL
DirectX - Microsoft Proprietary 3D effects - Works on the Hardware Abstract Layer

You don't need to know companies.

*whew* I think I'm done babbling.. Class is boring :P

Sartan

Oh, wait, did I mention I didn't have any display problems that went further to simple debugging on my A+? :P IE Check the contrast on a
monitor.

Chadae

Thanks alot for that info Webmaster & Sartan!!!! I had skipped over to processors (i posted another question) But I will definitely go over this information!!

bellboy

a lot of study material goes into it in great depth, but i don't expect it to be questioned thoroughly.

perhaps it's best to know that some o/s can change screen resolution without rebooting and that one way to solve a problem of a blank screen is to boot into safe mode.