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Great Hierophant
August 20th, 2011, 07:26 PM
Really bad things will happen if you do any of the following :

1. Moving a system or a vintage hard disk drive without parking the hard drive heads. Early drives do not have an auto-park feature, so if you care about what data is on the platters, you must use a park utility. Failure to do so and the drive heads may land on a sector that has data onto it, potentially destroying that data if the heads move or subject it to unwanted magnetism. Check the drive's info to see whether it supports autopark.

2. Writing to a double density 5.25" disk in a high density drive (unless the disk has never seen a low density drive). If using a pre-formatted DD 5.25" disk, such as that containing commercial software, you can read it all you want in a HD drive, but never, ever write to it. Put some electrical tape over the write tab just to make sure the program or its install does not write to the disk either. You can format and write to blank DD diskettes all you want in the HD drive, but their readability in a DD drive is not guaranteed.

3. Turning a power supply on without a minimum load (at least the motherboard and one disk drive should be connected). Early PC power supplies have overvoltage protection, but they do not cope with undervoltage or current well. Do not plug in a power supply without it being connected to anything. The +5 and +12v lines need something to run, and a motherboard by itself may not need enough of the +12v. Put some cards in there or a disk drive. You don't want to burn out avintage power supply.

4. Using a monochrome TTL monitor with a color graphics adapter or a color TTL monitor with a monochrome display adapter. This can easily lead to blown monitors, as each card will send a scan rate to the wrong monitor which it was not designed to handle. They may use the same connector and often look the same, but unless you know your graphics adapter supports the opposite type of monitor, keep them apart.

5. Using floppy drives whose working order is uncertain with important disks Never use important disks with an untried and untested floppy drive. A dirty drive head may leave its mark on the disk, a broken mechanism can chew up floppies.

6. Unnecessary or rough plugging in and removal. This will inevitably lead to broken things. Pulled sockets, snapped off pins, stripped screws, worn out slots. If you do not have a need to pull a chip, then don't. DIP chips and sockets are not designed for repeated removal. If you have to remove a chip, above all else be gentle and patient. Use a chip puller when possible. A broken pin on a chip that is not easily replaceable may mean a useless system, board or drive.

7. Failing to keep your systems clean. Systems work much more reliable when clean. If you buy a new system, if the first thing you do is check it out to see if it at least seems to be working, the second thing that you must do is clean it out.

8. Plug computer equipment into anything that is not surge protected. If lightning strikes, even with a ground pin, such a surge could fry your computer. Always plug your equipment into a surge protector.

10. Reversing a plug in. If your cable is not keyed, then remember that pin 1 is the pin closest to the red stripe. If the ROM chip goes into a socket, there should almost always be a notch or a dot to tell you to line up that with the silkscreen or socket when you plug it in. Reverse the cable or the chip, and you could be sending +5v on the GND line, which leads to a short circuit. If you can't see any pins numbered on the board or a notchless socket, research! If the socket/port is not symmetrical then don't try to jam it in the wrong way if you can't see it.

Chuck(G)
August 20th, 2011, 08:24 PM
If lightning strikes your power line (direct strike as opposed to the more usual induced surge), nothing will save you, not even the most expensive surge suppressor in the world. The average negative lightning bolt carries a wallop of 500 MJ; positive lightning makes boom with an average energy of about an order of magnitude greater. I know of no surge suppressor that will absorb and dissipate 5 GJ.

If you live in a part of the country prone to severe thunderstorms (believe it or not, there are parts of the country where lightning is a very unusual event), the only sure fire approach is to unplug your equipment; find a good book, pour a glass a wine and wait the storm out.

GottaLottaStuff
August 20th, 2011, 08:41 PM
Leaving your vintage PC out in the cold for a while and then starting it up before it warms up will kill it too. Lost a hard drive and a power supply fan that way once. The lubricant sets up and then the bearings fail before it thaws. :(

DOS lives on!!
August 21st, 2011, 04:41 AM
1. Moving a system or a vintage hard disk drive without parking the hard drive heads. Early drives do not have an auto-park feature, so if you care about what data is on the platters, you must use a park utility. Failure to do so and the drive heads may land on a sector that has data onto it, potentially destroying that data if the heads move or subject it to unwanted magnetism. Check the drive's info to see whether it supports autopark.
I always park old HDDs before I move them, even if it's across the room. I guess I'm a little scared of data loss. It is, however, safe to turn off any computer running DOS (or similar OS) without parking only when no programs are running.

Now, another question this brings up. Is it OK to run parking utilities from the hard drive or must they only be run from a floppy disk? I know SHIPDISK was required to be run from a floppy disk, but what about other generic parking utilities.


5. Using floppy drives whose working order is uncertain with important disks Never use important disks with an untried and untested floppy drive. A dirty drive head may leave its mark on the disk, a broken mechanism can chew up floppies.
Or it can't read the disk because of a dirty head, throwing up that annoying error, "Not Ready Reading Drive A."

I have a cleaning dsk, but the cleaning solution has long been dried up. Is there some sort of other "liquid" that I could use as the cleaning solution?


7. Failing to keep your systems clean. Systems work much more reliable when clean. If you buy a new system, if the first thing you do is check it out to see if it at least seems to be working, the second thing that you must do is clean it out.
Dust bunnies were making my tape drive not work properly. After a quick air blast, it's running smoothly.:)

krebizfan
August 21st, 2011, 06:29 AM
I always park old HDDs before I move them, even if it's across the room. I guess I'm a little scared of data loss. It is, however, safe to turn off any computer running DOS (or similar OS) without parking only when no programs are running.

Now, another question this brings up. Is it OK to run parking utilities from the hard drive or must they only be run from a floppy disk? I know SHIPDISK was required to be run from a floppy disk, but what about other generic parking utilities.

The disk parking program I used ran fine from when launched from the hard disk. Actually, it parked both hard disks. I had it as part of a batch file that made sure the disk cache was saved before parking the drives that I would run prior to powering off. Disks still started having problems a few years ago but 20+ years of service out of a 20MB Miniscribe was satisfactory to me.

Chuck(G)
August 21st, 2011, 07:39 AM
I've never parked an MFM hard disk and I'm still using the 30MB Quantum Q540 in my XT clone after 20-odd years and the box is one that moved a lot.

I might consider parking a drive if I'm getting ready to ship it.

Great Hierophant
August 21st, 2011, 07:53 AM
If lightning strikes your power line (direct strike as opposed to the more usual induced surge), nothing will save you, not even the most expensive surge suppressor in the world. The average negative lightning bolt carries a wallop of 500 MJ; positive lightning makes boom with an average energy of about an order of magnitude greater. I know of no surge suppressor that will absorb and dissipate 5 GJ.

If you live in a part of the country prone to severe thunderstorms (believe it or not, there are parts of the country where lightning is a very unusual event), the only sure fire approach is to unplug your equipment; find a good book, pour a glass a wine and wait the storm out.

You forgot to mention lighting the candles.




Or it can't read the disk because of a dirty head, throwing up that annoying error, "Not Ready Reading Drive A."

I have a cleaning dsk, but the cleaning solution has long been dried up. Is there some sort of other "liquid" that I could use as the cleaning solution?



Use Isophrophyl Alcohol, 91% or higher, which you can get at any drug store.

I have never parked the drive heads on my ST-225 and after moving it and installing it I have never had an issue with destroyed data. Maybe mine was a later model where they added an auto-park feature.

barythrin
August 22nd, 2011, 07:06 AM
You can run park from the hard disk. It'll load into memory, move the drive head to the park sector, then leave you with a message (I think it says something like the system is now ready to be moved or it was parked)* (that was my memory from Zenith which I think did have it's own park command.

Either way though it just parks it so you can turn it off afterwards and the system resumes once it's back on.

Chuck(G)
August 22nd, 2011, 08:28 AM
This does tie into the topic, but how many have "positive off" provisions (not soft-power buttons) on their gear? That's one good thing you could say about the BRS--when the equipment was off, it was disconnected from the power line. What with the soft-power connection now popular with computers and appliances, I wonder if damage from power line surges is more common...

barythrin
August 22nd, 2011, 09:15 AM
I always wanted to sue a company (ok talk not really) for loss of equipment during a storm for it not truly being turned off despite the power button being in an off state. Nothing bothers me more than opening up a computer that's plugged in but off and seeing a powered on LED. It used to be an almost safe ground to have a system turned off but plugged in, now it seems like an electrical hazard.

Chuck(G)
August 22nd, 2011, 09:25 AM
I always wanted to sue a company (ok talk not really) for loss of equipment during a storm for it not truly being turned off despite the power button being in an off state. Nothing bothers me more than opening up a computer that's plugged in but off and seeing a powered on LED. It used to be an almost safe ground to have a system turned off but plugged in, now it seems like an electrical hazard.

And if I want to use an external power switch, very little modern equipment has any way of disabling the "power" button, should you elect to use a "real" external power switch.

Rick Ethridge
August 22nd, 2011, 03:13 PM
Never, EVER turn on a computer with a floppy in the drive. Disk corruption is possible especially in very old systems.

Chuck(G)
August 22nd, 2011, 03:32 PM
Never put a disk in a just-cabled floppy drive without first checking to see the drive select light is off. If it's solid on, it's a sign that you've got a connector either reverse, or "staggered". Whatever, it'll do a wonderful job of erasing whatever track the head happens to be on.

DonutKing
August 22nd, 2011, 10:55 PM
I have never parked the drive heads on my ST-225 and after moving it and installing it I have never had an issue with destroyed data. Maybe mine was a later model where they added an auto-park feature.

Apparently you're just lucky:

http://www.bitsavers.org/pdf/seagate/Seagate_Universal_Installation_Handbook.pdf



All Seagate disk drives, with the exception of the ST213, ST225, ST225N and ST238R products, have an automatic read/write head parking function at power-off. This feature does not require operator intervention.

I was concerned that my ST251 required parking, and found that link while researching info about the drive.

Chuck(G)
August 23rd, 2011, 09:30 AM
Sometimes, you can hear a "click" as the drive powers off--that's a pretty good indication there's some sort of head-parking or unloading mechanism in play.

strollin
August 23rd, 2011, 09:43 AM
Never, EVER turn on a computer with a floppy in the drive. Disk corruption is possible especially in very old systems.
How do you propose booting a floppy-only system then? Are you saying, power on the system, then put the floppy in? I have always booted my floppy-only systems with a floppy in the drive and haven't encountered any problems.

DOS lives on!!
August 23rd, 2011, 11:48 AM
How do you propose booting a floppy-only system then? Are you saying, power on the system, then put the floppy in? I have always booted my floppy-only systems with a floppy in the drive and haven't encountered any problems.
Yes, turn on the computer, then put the floppy in. I guess an electrical surge would make its way through the head and erase the disk.

tezza
August 23rd, 2011, 01:38 PM
Yes, that's what I do too. Turn on, check that the floppy disk light is on THEN insert disk. I just feel it's safer that way.

Tez

strollin
August 23rd, 2011, 01:48 PM
From the "Guide To Operations" for my 5150:

If Your Computer is Off

1. Insert the DOS Diskette into drive A: and close the diskette drive cover.
2. Turn on your printer, if you have one, a video monitor or TV, and then the computer.

Seems pretty straight forward to me and the way I've been booting my 5150 since 1984. In all that time this is the first I ever heard of doing it any other way.

tezza
August 23rd, 2011, 02:23 PM
Seems pretty straight forward to me and the way I've been booting my 5150 since 1984. In all that time this is the first I ever heard of doing it any other way.

Maybe it's safer in some machines than others. My first disk-based machine was a System 80 (a TRS-80 Model 1 clone). Wisdom for that was NOT to start the machine with a disk in the drive. I just carried that behaviour over to all other floppy-based machines, which was a conservative approach.

Tez

NeXT
August 23rd, 2011, 02:37 PM
The Apricot systems were also OK with the disk being on the drive when you powered them on because the head is raised off the disk surface when it's not being used.

mikey99
August 23rd, 2011, 05:51 PM
Never, EVER turn on a computer with a floppy in the drive. Disk corruption is possible especially in very old systems.

I was told the same thing way back in the early 80's when I first started using the IBM PC.
I assumed it had something to do with the power on surge possibly causing the drive to write to the diskette.
I was also advised to always remove the diskette before powering off because the drive
could inadvertantly write to the diskette when power drops.

Chuck(G)
August 23rd, 2011, 06:13 PM
I was told the same thing way back in the early 80's when I first started using the IBM PC.
I assumed it had something to do with the power on surge possibly causing the drive to write to the diskette.
I was also advised to always remove the diskette before powering off because the drive
could inadvertantly write to the diskette when power drops.

Well, it may happen, but it's never happened to me and I've used a lot of floppies over the years. It might conceivably be an issue with a certain drive brand or model, however.

Agent Orange
August 23rd, 2011, 06:59 PM
Well, it may happen, but it's never happened to me and I've used a lot of floppies over the years. It might conceivably be an issue with a certain drive brand or model, however.

Power down a Tandy Model II and your 8" disk was gone.

Chuck(G)
August 23rd, 2011, 08:11 PM
I could see power down, but only if the heads on the 8" drive loaded. No, it's powering up that's being discussed. I know I've started my Model 16 (close enough to your Model II) many times with both disks inserted with no issues.

mikerm
August 23rd, 2011, 08:15 PM
I guess I really would like to know why that could even be an issue, as far as my knowledge of floppy drives go, the head wouldn't be moving, nor the disk spinning unless the drive was getting instruction to do so, so I can't make any logical conclusion on why either power on or power off would be an issue.

In personal experience, I have done both, and never had any problems.

Chuck(G)
August 23rd, 2011, 08:20 PM
Well, the power-down scenario is plausible. The disk is spinning and drive signal lines are active-low, so SELECT and WRITE GATE could conceivably drop low enough to activate the write circuitry on the drive, particularly if the drive was already selected.. But on power-up, I can't see it.

krebizfan
August 23rd, 2011, 09:11 PM
I seem to remember that some disk packs and Syquest drives suggested strongly the drive be turned on (but offline for disk packs) before the media was inserted. Couple that with a misremembered bit about the Coleco Adam's tape drive issue and another "Old Nerds Tale" was made.

Agent Orange
August 23rd, 2011, 09:17 PM
I could see power down, but only if the heads on the 8" drive loaded. No, it's powering up that's being discussed. I know I've started my Model 16 (close enough to your Model II) many times with both disks inserted with no issues.
Never had a problem with any Tandy on power up with a floppy in place. The Model II with an intenal floppy and the 3-bay external floppy console would zap all 4 on a power failure or if the office secretary inadventently flipped the power switch. Don't know about the Model 3 or 4 though.

barythrin
August 24th, 2011, 08:21 AM
I was gonna stay quiet since this is a PC compatible thread but that's one of the biggest issues with an Amiga. Never remove a floppy disk while the drive light is on or it will likely wipe out the media. Huge issue vs PC where I've done that for years (quick mistake, panic, yank disk out before it writes, disk is fine) but with the drive heads down in an Amiga I think there's some magnetic force or something that the drive passes by which erases data in that location on it's way out of the drive. Basically turn off the system before ejecting a drive if the system is hung and actively playing with the floppy.

RJBJR
August 28th, 2011, 10:04 AM
Never, EVER turn on a computer with a floppy in the drive. Disk corruption is possible especially in very old systems.

I had a Bondwell B200 that would damage a disk in either 720k drive if I forgot to pull the disks during power down. IIRC, that was one of the "dont's" in the manual.

Chuck(G)
August 28th, 2011, 10:07 AM
"On" is not the same thing as "off". The Olivetti M24 PC used drives with head-load solenoids, so chances of corruption with the drive deselected were about as close to zero as you could get. IBM never bothered with that level of security, except for their equipment that used 8" drives.