Changeing your mind in the middle of production GAWWW

[Ferroto]

So I was looking at 2 old AGP video cards and one thing that keeps bugging me is leads that go nowhere. now I've wondered about this for years and after watching dilbert i came to a realization.... this is the result of MBA managers giveing engineering advice to engineers otherwise known as "Micromanagment" take this card for example it clearly was intended to sport a DVI port but this was removed after the PCB was developed a decision that should have happened much earlier on in the development phase.


Also this other card has a tonne of missing SMD components. Theres also according to the silkscreen a missing BT869 to encode the composite signal also we're left with a place for an RCA jack for the composite video cable.

[DJPhil]

I've seen a lot of this as well. I'd always assumed they made several models with different feature sets usable from a single pcb design. I suppose it's probably more likely attributable to the forces of evil, as I imagine it must be a bit crazy to design as the options grow.

Now you've got me thinking about what sorts of gear I haven't seen this happen to!

[xani]

A lot of things that otherwise would've been great products ended like that coz some management type thougth saving on some parts worth 2-5% of final product price

[charliex]

Its just normal product lines, components cost doesn't really come into it, although if you're selling 100K*units then a DVI connector is fairly significant.

If you feel bad about the agp card, consider the lamborghini superleggera they remove a bunch of stuff and charge you another 50-100$K, same thing goes for the porsche GT-3R, and the Ferrari 430 challenge.

[desolatordan]

I wouldn't "blame" this on business people. This is engineers saving money on PCB's, and keeping their options open for integrating features in the design process.

[Ferroto]

I wouldn't "blame" this on business people. This is engineers saving money on PCB's, and keeping their options open for integrating features in the design process.

That's what I figured, I just always thought it was weird to see components missing.


I'm not too worried though, I'm planning on donating those cards to education. (I'm going to learn to solder SMD's )

[Simon]

I've seen it on just about every computer PCB I've ever looked at going back to the days when you could actually purchase the extra VRAM for your card. I've had motherboards with missing raid chips clearly an options open thing and making one prodict that can be made into an upgraded version without redesigning the PCB.

you will even spot this in TV mainboards it's just a fact of manufacturing.

if you want to here an evil story about cost saving what about the black cabs that were busting into flames for no reason (about 2 years go my company supplied the radiators), guess why ? because on a car worth over 20'000 pounds they decided to save just £ 7 on a heat shield, result ? it was only down to a lot of luck that nobody was ever injured/killed, from what I heard you had about 30 seconds to get out as the cads were going up in flames like they had been hit by a misile

[Zero999]

I was thinking about this kind of thing yesterday and I realised that not only could some of today's products could be better at little extra cost but the same goes for products of yesteryear.

Remember the crappy old VGA card?

It could've been much better at very little or not extra cost.

It had 256 Kilobytes of RAM, 2 Megabits.

The highest supported resolution was 640x480 4-bit, 16 colours but it was only using 1.17Mb, (150KB) the card could've theoretically been designed to use 6-bit colour at the same resolution and still had some RAM to spare, 640x480 6-bit with 64 colours would look much better and use = 1.85Mb (225kB).

There could've been a 320x240 18-bit colour mode - the card had a 18-bit DAC so why not use it to its full potential?

Of course later on some geeks discovered mode X which enabled resolutions up to 360x480 with 8-bit colour using the original monitor or 400x600 using a SVGA monitor but the same old crappy card and was used by a few games.

[Simon]

maybe it was also due to the speed of the then video processors ? video processing is a heafty task in fact any andnalog to/from digital conversion requires the carrying of a lot of data, for example my modern (well as of a couple of years ago maybe) VGA card supports two monitors but cannot cope with a lot of activity on both at once.

[charliex]

6 bits doesn't really work well for speed or ease of use, 4 bits does, it makes a lot of the rendering tricks used not work as well.

The speed is definitely part of the issue, mode x is just planar VGA with a square aspect, abrash just made it popular, its always been part of VGA. Most used it as 320x200/240 it was just too slow otherwise. (as well as making sure the banks make sense)

[Zero999]

I don't see how 6-bit would be any worse than 4-bits?

If I remember rightly, in the 4-bit planer mode the bits were addressed as planes, you set a register via an I/O port according to which planes you want to write to. For example if you wanted to put a white pixel at the top hand corner of the screen, you set it to write to all the planes (white was 1111) and set the first bit in the first byte of video memory to high. The procedure would be the same on a 6-bit planer mode except you'd set the register to 111111. The good thing about planer mode was it meant you could write to 16 pixels simultaneously  which would still be true in a 6-bit planer mode.
http://en.wikipedia.org/wiki/Bit_plane

It's a long time since I've done any of this, sorry if I'm wrong. I just recall thinking it was odd that the VGA card wasn't better.

[charliex]

6 bits doesn't pack well into an 8/16 bit arch though, you can store two pixels per 8 bit, which means smaller LUTs etc, whereas 6 bits doesn't match as well. How would you represent the 6 bits per pixel in the code/data ?

mode x is byte per pixel, has page flipping and it fits into the cache arch well, so thats what makes it better than mode 13. Perhaps you're mixing up modes? , MCGA mode is the normal 256 colour 320x200 that mode x replaces, not the 16 colour old VGA mode. you can write 6 pixels at a time, and it optimises really well around rep stosb's etc.

since i think we're mixing up the mode 12 vs mode 13 and mode x, there are some differences, so we might be talking at cross porpoises.

[embedded]

In industry boards are stuffed to different levels often.

Extra features cost extra money.  We do not put the parts in or more importantly test the features that you didn't pay for.

You very often see this on motherboards.

We do it all the time for industrial boards.

Microchip and other semiconductor suppliers also do this all the time.  The same die make multiple micro-controllers but if you didn't pay for 64k but 32k you either get a fall out chip or just one that that part of the flash was not tested.  The most expensive part of a micro-controller is test time!

[Simon]

well it is after all the same philosophy as applied to the rogol scopes, you payed for 50 MHz so you got 50 MHz, never mind that they were already fit for 100 MHz

[Zero999]

6 bits doesn't pack well into an 8/16 bit arch though, you can store two pixels per 8 bit, which means smaller LUTs etc, whereas 6 bits doesn't match as well. How would you represent the 6 bits per pixel in the code/data ?

The 4-bit VGA mode wasn't a packed pixel pixel mode but a planer mode as I said above.

There were four bit planes, each was effectively a monochrome bitmap taking up 640x480/8 bytes which enabled you to write 16 pixels at a time in old 16-bit mode and 32-bits at a time in protected mode.

A colour register set which plane you wrote to, with all bits set high it would write to all planes simultaneously.

A 6-bit colour mode wouldn't have been any more difficult to implement, it would've just needed a couple of extra bit planes and it would've looked a heck of a lot better.

Planar graphics were very common in the 80s and early 90s before 256 colour modes were common. The BBC computer used have a 3-bit colour display capable of 8 colours. I didn't do any assembly programming for the BBC so don't know for sure but I'm pretty certain it would've used a planar graphics mode.

http://en.wikipedia.org/wiki/Planar_(computer_graphics)
http://en.wikipedia.org/wiki/Bit_plane

mode x is byte per pixel, has page flipping and it fits into the cache arch well, so thats what makes it better than mode 13. Perhaps you're mixing up modes? , MCGA mode is the normal 256 colour 320x200 that mode x replaces, not the 16 colour old VGA mode. you can write 6 pixels at a time, and it optimises really well around rep stosb's etc.
since i think we're mixing up the mode 12 vs mode 13 and mode x, there are some differences, so we might be talking at cross porpoises.

If I remember correctly, mode X also had four planes but it was different to the 4-bit colour mode in that the plane 1 consisted of every pixel dividable by four, the second every pixel dividable by four plus one, the third every pixel dividable by four plus two etc. This enabled you to put up to eight pixels on the screen with a single 16-bit write or a 16 with a 32-bit write.