Design flaws in classic computers

[SiliconVandal]

design flaws in classic computers

design flaws in classic computers

re: the BBC Model B, of which not much said so far -
- it used the less-common symmetrical DIN-5 connector for the
Serial Port, and this could be plugged in 2 different ways...only
one of which worked correctly, of course. Also used the equally
less common but well-intentioned RS423 signal levels, which
means it won't talk to most RS232 ports without a spot of
voltage level-shifting.
- it had 5&1/4" floppies but with a non-standard format and a
non-hierarchical filing system (DFS) which severely limited the
no. of files you could store. Various third-party fixes existed to
overcome this, but Acorn finally replaced the old 8271 disk chip
with the later 1770 device and upgraded the software to ADFS.

 

[Genghis7777]

The first thing that comes to mind is the NeXT Cube MO drive.
Yes it was the first on the market and yes it was quite nice to use but here we are in 2009 and out of the thousands that were made, I only know of five or six that still work. All the others have died in some different way (won't load, won't read, won't eject, won't spin etc.).
It's a bad idea to put a drive that unreliable in a good system AND make it proprietary so you can't replace it with much else.

The second is the handwriting recognition on the Newton MessagePad. God damn it's so annoying that whenever I have to enter stuff in I just use the on screen keyboard.

Then there is Sync on green....I'm not going to touch that.

What model Newton do/did you have? The NOS 2.x machines had much better HWR.

 

[GADFRAN]

For my input -

Kaypro coiled keyboard - computer connection cord !!!

So many just loose it and you are dead in the water.

Compaq fixed it by keeping it connected. I think some Osbornes also did this. So why not Kaypro, even after the first Compaq came out ?

Then the "common fix" - NOT - it may look like a phone coiled cord but it is not - oops !!!

Otherwise, as many know, Kaypro did a great job in designing their early computers - e.g., Kaypro II, etc.

Thanks Tezza for the post to get us thinking.

Of course, today - what are those genius engineers and managers still doing to make similar such gross errors - let us hear it from all you out there with your own "gripes" about modern systems, so we can compare with vintage systems, which did not do those more modern gross errors.

"And so it goes" as my philosophical wife always says !

Somehow we still continue to survive despite it all !!!

Frank

 

[Bobthearch]

Speaking of Kaypro...

The sharp metal corners on a 30lb portable computer. Ever carry one while in a hurry? Talk about painful!

The non-standard video plugs on Sun SparcStations. Jerks.

16K memory module on the Timex Sinclair causes enough television interference to be unusable. Design flaw or defective module?

 

[tezza]

- it had 5&1/4" floppies but with a non-standard format and a non-hierarchical filing system (DFS) which severely limited the
no. of files you could store. Various third-party fixes existed to
overcome this, but Acorn finally replaced the old 8271 disk chip
with the later 1770 device and upgraded the software to ADFS.

I'm not sure I'd call the DFS OS a "design flaw". It's more just a product of it's time. After all, there wasn't really a standard as such when this operating system for the BBC first came out. Other 8-bits (Tandy, Commodore, Apple, Atari etc.) all had their own incompatible systems. The nearest "standard" there was for 8-bit computers was CP/M but then it was really only a standard for business micros. Even then, it wasn't heirachical.

I see a design flaw as being a problem that should have been forseen if the designers had thought about it hard enough, given the technology they had available. Of course technology advanced quickly so what might seem a bad idea in retrospect actually may have been a good solution given the constraints at the time.

Tez

 

[leeb]

Adding my 2 cents...

Adding my 2 cents...

Considering the effort Ive put in recently...

Id say the power-up issue on the Tandy 2810 and its relatives (such as the Panasonic CF270, and apparently, the GRID 1720).

Both the 2810 and 270 have the same powerup issue and Im sure that if I find it on the 2810 it will fix the 270.

But for now, Im forced to go blind with schematics and ITSY-Bitsy-teeny-tiny parts! :shock:

 

[sombunall]

How about a fan for the 1541 floppy drive? If you didn't use one eventually it would give you the blinking red light and you'd have to let it cool and start loading all over again.

 

[nige the hippy]

re: the BBC Model B, of which not much said so far -
- it used the less-common symmetrical DIN-5 connector for the
Serial Port, and this could be plugged in 2 different ways...only
one of which worked correctly,

They did get it wrong, I think the original intention was that one way up it was DTE the other way it was DCE (kind if a built in null modem arrangement - brilliant) and someone F***ed up the PCB.
The tatung einstein has the same connector, with the arrangement corrected.

 

[tezza]

They did get it wrong, I think the original intention was that one way up it was DTE the other way it was DCE (kind if a built in null modem arrangement - brilliant) and someone F***ed up the PCB..

This is interesting. A long while ago I built a serial connector for my BBC and I couldn't for the life of me get it to work. I ended up replacing some of the serial circuity and it STILL didn't work!

Are you telling me I could have had the thing upside down?? Next time I drag out the BBC, I must check this out.

Tez

 

[vwestlife]

The biggest design flaw in the commodore and atari computers was they taylored to much to kids and games and lacked a serious 80 column display ability.

Atari did make an 80-column display interface for their 8-bit computers, but in typical Atari corporate mismanagement style, most of the production inventory remained locked up in a forgotten warehouse until after they had stopped selling computers. I remember reading Atari's 1994 financial report, and it described how the company had to dispose of a large inventory of old, obsolete, unsold Atari 2600 games and 8-bit computer peripherals.

 

[antiquekid3]

How about a fan for the 1541 floppy drive? If you didn't use one eventually it would give you the blinking red light and you'd have to let it cool and start loading all over again.

Not to mention the fact that the drive head has to hit up against the stop like a woodpecker...I think that's my biggest problem with them. The two drives I have are both out of alignment! It'd seem as though they could've had a sensor to detect when it was at track 0.

Kyle

 

[saundby]

The IMSAI FDC-2 floppy disk drive original cabinet didn't provide airflow, leading to the nickname "The Pizza Oven". IMSAI first gave people a sheet of paper with a hole drill pattern on it as a fix. As they say these days, "epic fail." I recall the PCS-80 having serious heat issues in the first batches, too.

The basic SOL-20 board, once built, then had to be partially disassembled to add the memory expansion slot when you were ready to add more RAM to the system.

The Processor Technology 32K and 64K memory boards had their own refresh circuits, to avoid slowing down the CPU. They worked, most of the time...

PT also used the finicky Persci 270 floppy disk in the Helios II drive subsystem. It needed adjustment if you so much as slid it along a desk. Of course, it did have the cool futuristic feature of sliding your disks out of the slots for you.

The Ferguson Big Board I didn't have a drive motor relay, the drive motors ran constantly while the system was on (another fix from MicroC took care of this one.)

 

[BradN]

Design flaws in Sanyo MBC-55x home/business computer:

Keyboard was custom but used the same DIN-5 port, made interchanging keyboards impossible. No alt key and only 5 function keys leads to convoluted key combos to press these missing keys, not all combinations are possible.

System must steal 16KB of the 48KB video RAM from main memory. Its placement is not friendly to non-sanyo MS-DOS when more than 256KB of RAM is installed, but if that much RAM is present, CGA video is probably on the same card which may make this less of an issue.

Onboard video is organized into graphic blocks of 8col*4row. It would have been more suitable for character display if they went with 8x8, and more suitable for graphics if they went with 8x1.

Page flipping can be used to support 640x400x1bpp interlaced output, but the CRTC chip apparently doesn't support interlaced output - it could probably be done with a very convoluted software hack that reprograms the CRTC every frame - this is a challenge in itself because there's no proper VSYNC feedback to tell when to do this, so advanced timer trickery must be used to track the video output position.

Floppy controller supports single and double density disks, but the density select pin is hardwired to double density. Need a hardware mod to use single density.

Compatibility flaw: None of the motherboard hardware except RAM, CPU, and FPU are IBM compatible - either from chip choice or port address placement. Applications must stick to DOS/BIOS calls or be specially ported to this machine. A CGA expansion card improves compatibility a lot, but the add-in cards are proprietary and hard to find.

Software flaw: "Fake" timer driven RTC loses time when the floppy is accessed (CPU's full attention is needed to transfer data) - can be overcome through software by using the 2nd chained timer channel.

Software flaw: No BIOS in ROM even though the chip is large enough (8KB, socket supports 16KB) to fit a simple one. BIOS is provided as part of IO.SYS and loaded with a custom boot sector. I'm developing a replacement BIOS that currently can run FreeDOS.

These flaws almost all derive from cost saving measures (non-IBM compatible cheaper chips, omission of a DMA controller entirely, reduced chip count address decoding, perhaps rushed software development).

All this said, the motherboard is, without exaggeration, beautifully designed with all chips facing the same direction (none upside down), and only 1 or 2 sideways depending on motherboard version. No jumper wires or other post-manufacture tweaks. It must have been a nightmare to design like that on a 2 layer board.

 

[vwestlife]

Software flaw: No BIOS in ROM even though the chip is large enough (8KB, socket supports 16KB) to fit a simple one. BIOS is provided as part of IO.SYS and loaded with a custom boot sector.

I believe the Tandy 2000 is the same way. When I had one, I noticed the BIOS copyright message would only appear after the OS had started loading from disk.

And as for those Sanyos, I heard that the floppy drive access light stays on all the time when the drive lever is closed.

 

[k2x4b524[]

wireless keyboard idea of the pcjr was ahead of it's time, however the layout left something to be desired, but my biggest blitch about it is the sidecar slots..... couldn't they just have as easily made it ISA and sold a slot box?

 

[nige the hippy]

The wireless (infra-red) keyboard of the Apricot Portable was quite remarkable.
In many light conditions it was pretty unreliable, to remedy this, Apricot supplied fibre-optic "wires" to connect it to the system. So much for a good idea!

 

[Raven]

While we're on the (relatively narrow) category of infrared keyboards, I have one by Cherry that's compatible with the PCjr (at least by cable) and also a receiver that was sold separately. The receiver allows it to be used on any XT computer - pretty cool. :D The receiver also includes a port for the PCjr keyboard cable (for the Cherry keyboard) which also likely means it's compatible with any actual PCjr keyboard - win.

The cables, both on the PCjr and this keboard, were of course due to the inherent problems with infrared keyboards, especially when multiple units are in use at once.

 

[Anonymous Freak]

My favorite is the "pizzabox" line of Macintoshes that were "DOS Compatible". Specifically the Quadra 610 DOS Compatible and Power Macintosh 6100 DOS Compatible. What made these especially fail-worthy was the fact that the power button is right next to the floppy drive.

The auto-eject floppy drive.

That doesn't have a physical eject button.

Which meant that a regular PC user that had just switched would be very likely to push the button next to the floppy drive when they wanted to eject the floppy. The button that instantly turns off the computer.

 

[Dwight Elvey]

I get my medical care from the Veteran's Administration, so I have an electronic medical record. Best thing to hit medicine in a long time. Anyway, one day I notice my doctor is moving one of his hands off of the keyboard to use the mouse like every five seconds so I tell him that the next time I come I will bring a list of Windows keyboard commands for him to learn. By the visit after that he was entering data at lightspeed, never using the mouse, or at least not much. I still like to use the keyboard to accomplish what the mouse can do. Takes me back to my version 1.02 days.

I wonder if the commands are in the help section of XP/Vista that doesn't pass for a manual. Anybody?

I really like the fact that "scroll lock" works now, too.

Sean

Hi
I'm using system 7 and when reading email, I'd like to cut and paste.
I've had to revert to key board for this because I still haven't figured
where the menu is for it.
Jef Rasken would have loved the story about the Doctor. He knew
from the begining that the mouse was being used wrong.
Dwight

 

[kb2syd]

How about HaltAndCatchFire on the TRS-80 model II. There were a set of out instructions in basic that could actually burn out the video circuitry.