Copyright 1984 by ABComputing July 15, 1984 ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ» º Full and Fractional Size Floppy Drives º º º º by º º º º Ken Holcombe º ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍͼ ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ Introduction ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ I am increasingly being asked what I think about half-height drives. Are there any real advantages or disadvantages? How compatible are they? If they are better, how come some of them are cheaper than full heights? Am I really getting a good deal? ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ 2/3 Height? ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ First of all, there is such a thing as a 2/3-height as well as the now popular 1/2-height floppy drive. BASF, among others, makes a 2/3-height drive. This drive has a belt-and-flywheel drive system very similar to the Tandon and CDC full size drives. (If you aren't familiar with the innards of a full size drive, the drive mechanism is similar to that found on an eight-track or cassette player; that is, a belt connecting the motor to the spindle or hub. On disk drives, the belt is made of much better material and lasts longer.) ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ The Big Difference ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ There is one notable difference between a 2/3-height or smaller drive, and a full size drive: solenoids! While repairing a BASF 2/3-height drive recently, I found that I was unable to get an RPM reading with my drive-alignment software. It seems that the head has a solenoid that allows the head and pad to be pushed against each other only when a read or write operation occurs. With a double-sided drive this means that the two heads on opposite sides of the disk are pushed against the mylar only when needed. Time out now. I know this is a magazine for advanced users, but I hate to think of leaving someone behind just because I made some false assumptions. I can hear somebody out there saying, "I thought the head wasn't supposed to touch the disk." Yes, Virginia, there is such an admonition, but it applies to hard disks. The mylar floppy disk needs to be pressured (lightly) against the head the same way a cassette tape is pulled against the head. Time in now. The full-height drives used in the IBM-PC (and many other computers with 5.25 inch full-height drives) do not use these solenoids on the head(s). The head and pad (or two heads in the case of a double-sided drive) are pushed together against the mylar disk when the door is closed. ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ Time Delay ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ Now, let's get back to why I couldn't get a reading while trying to adjust that BASF 2/3-height drive. I had used this same software (Readiscope) on the full size drives and it worked great. The difference in performance was due to the length of time it takes for the head solenoid to activate and do its thing. With most software, the extra time before the head is ready to read or write is not critical; with the software I was using, it was. I manually held the head solenoid in the activated state before I pushed the key to start the RPM check routine and everything worked fine. Now for the important part: most copy-protected software could have the same problem with a fractional drive that my diagnostic disk did and for the same reason. That solenoid takes long enough to make the computer miss some of the special copy-protection information that the disk needs to read. ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ A Good Reason for Everything ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ Why did the fractional drive manufacturers go and put that stupid solenoid on the head? Well, obviously to save some wear and tear on the head(s). In fact, if you survey the computer industry you would find that most drives employ such a solenoid; it is those full size drives you have in your IBM-PC that are the exception to the rule, not the new fractional drives. ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ Solving the Solenoid Syndrome ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ So what can we do about that solenoid? Well, IBM helped by coming out with DOS 2.1 for you. It runs a little bit slower on access time, but cures most of the problems encountered with fractional drives. It doesn't, of course, help with a copy-protected software designed for the PC. If the fractional drives are here to stay, the software people will obviously have to do things differently. On some of the fractional drives, it's not too difficult to sidestep the solenoid mechanically and keep the head against the disk. ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ The Half-height ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ I now focus on the half-height drives, since not too many folks will buy anything else. It is the ability to put two half-heights where one full size drive was that makes the half-height so exciting to us. Selling 2/3-height drives these days is akin to being a horseshoe salesman (We could always make a game out of throwing them at picnics.) I know a good salesman can sell anything, but there is definitely a bigger market for tires. ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ Eat your Heart Out, Jobs and Woz ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ I know you've been dreaming of installing four half-heights in your PC and making your friend with the MACINTOSH gnash his teeth right out of his head. (You already dealt him a mortal blow when you told him about your 640K of RAM memory - see my article in PCFL/PCUG issue 1). Can we do it? Yes, we can do it, but I'm going to recommend something a little different before we're all through. ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ Installing Four Halves ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ Let's start with the physical mounting. Some half-heights need mounting brackets and some don't, but all in all, we won't encounter any insurmountable problems in mounting them. (Did you get that - insurmountable, mounting? I'm seeing a doctor about this, but I'm not being cured.) Now that we have them installed, we need to hook them up with cables. The power is easy. There are two power cables in your PC and you can purchase two "Y" connectors from Conroy LaPointe for $6 each and have four plugs with one Y connector for each half-height drive. It doesn't matter which one plugs into which drive. The power is there, waiting for the drive to be activated. It is a 34 conductor flat-ribbon cable that actually determines which drive is "A", etc. There are only two of these in your PC, but there is a jack on the back of the floppy-disk controller board for an external cable. We can buy or make such a cable (see my article in PCFL/PCUG issue 2) and then route it back to the inside of the PC and connect it to two of the half-heights for drives "C" and "D". ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ Cleaning Up the Snakepit ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ It does get a little crowded with the cables, but installing four half-heights can be done. Actually, the hardest part is getting that external ribbon cable back inside the PC neatly. Anything other than a dull chisel and a sixteen pound sledge hammer should get you good results. (It's so easy to slip when you're excited.) For less than $800, you can make Mike with the MAC literally croak. ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ Set the Switch, Dip ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ Don't forget to reset the little DIP switch 1. For three drives, section seven should be on and eight off. For four drives, seven and eight should both be off. Of course, you might have a problem with your RAM disk software if it insists on being drive "C" or "D". There are some RAM disk programs around that allow you more flexibility. ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ Is Your Power Supply Smoking? ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ You may want to know if all of these drives are overworking your power supply. Not really, because only one disk drive is operating at a time. In fact, the half-heights usually draw less current from the power supply than the full size drives, and in some cases half as much. ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ Less Muscle ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ The motors in half-heights are direct drive; there is no belt. This is generally a good move, but realize that some of the half-heights have less torque than full size drives. For example, if you received the "WORD" DEMO disk that was shipped in a certain magazine a few months ago, you might have received a squashed disk as I did. The data on my disk was fine, but it was audibly dragging. My Tandon full size drive spun it around OK, but many half-heights find the extra resistance too much for their motor which consumes less power and doesn't have its torque increased through a drive system. (Flywheel pulley larger than motor pulley.) ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ The Honorable Prophet ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ In spite of some of the disadvantages, I think that in a short time having a full size drive will date a computer in the same way that having a flathead engine dates an automobile. The half-heights obviously take up less room and some of them are easier on your power supply (in particular, the TEAC). The half-heights typically weigh 3-1/3 lbs. as opposed to 4-1/2 lbs. But don't expect a performance boost otherwise. They are certainly not faster. How reliable are the smaller drives? We'll have to wait and see, won't we? ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ My Dream Machine ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ Now for my recommendation: leave a full size drive in as drive A if you use copy-protected software. You can still install two half-heights on the right side. I don't know of any software using a a copy-protection scheme on any drive other than the default drive, not even 1-2-3's graphics disk. And if you can navigate around Mitch Kapor when it comes to copy protection, you've generally got it made. I'm talking about running the software on your machine, not copying it, so don't you legalists get all excited. My dream machine has (I'm still in the dreaming stage) a full size CDC floppy disk drive on the left, and a Teac half-height on the right, over a 20 megabyte half-height hard disk. Yes, there is a such a hard disk on the market and I'm going to describe it for you in a future article that is currently being developed under the title "The Over 2 Meg Media Mess or What Should I Buy Now that I Have a Hundred Floppies Lying Around?" (EDITOR'S NOTE: Titles like that require a hard disk for storage.) With this configuration, I could still easily copy from floppy to floppy, run copy-protected software, and store everything that wasn't copy-protected on the hard disk. I even know where to buy an auxiliary fan. ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ "Y" Disk Drive Power Cable Available From ³ ÃÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ´ ³ Conroy LaPointe ³ ³ P.O. Box 23068 ³ ³ Portland, OR 97223 ³ ³ 1-800-547-1289 ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ³ File Name: ÛÛ hard1.txt ÛÛ ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ