What the %$@# is up with links from certain other forums?

General Chit Chat
JimDrew
Member
Member
Posts: 18
Joined: Sun Jul 20, 2014 6:55 am
Location: Lake Havasu City, AZ

Re: What the %$@# is up with links from certain other forums?

Post by JimDrew » Mon Mar 13, 2017 4:53 pm

ckoba wrote:
Sat Mar 11, 2017 1:05 am
Well, to be absolutely fair, the Supercard is neither his idea nor his design. He may well secretly agree with you, but his ego (and his "borrowed" design") won't let him back down.

I did a bit of digging. In the 26 February 1986 issue of Ahoy! (and that date was chosen at random), there are two multi-page advertisments for Megasoft wares (pages 16-17 and 20-21). The first pair hawks "The Keymaster" (a parameter copier that couldn't copy itself) and the infamous Shadow. The second pair is the more standard Megasoft block-ad affair. The "Track Trap" is on the second page, right beneath the "Copy (de)Protection Manual (third edition)". Note that another copy utility on the same page has "by Jim Drew" under the title, so it is likely safe to assume that "Track Trap" was not written by him, but by others. I'll get to that in a minute.

I saw a copy of the "Track Trap" once. It was a pamphlet of instructions on how to add RAM to your 1541 to duplicate raw tracks. Not written nor designed by Jim Drew, but rather a company in Portland called PSIDAC and comprised of two people: Vic Numbers and David Thom. The same guys that wrote the (de)protection manual, actually. The PDF for the manual is on bombjack; I've not been able to find a copy online of "Track Trap", and suspect it may be rather rare. It would be interesting to see what logic family was used there, and thence if Jim just copied that too.

So there's circumstantial evidence that people were expanding the 1541's RAM to go the whole-track route *while* Megasoft was still doing "The Shadow" thing and long prior to Jim's "SuperCard" invention.

Jim wasn't first, nor best. There's a wonderful copyright notice from Bryce Nesbitt out there, allowing most of the known universe the freedom to use snippets of code he posted -- except Jim Drew, who he believed was a prolific thief. Commodore agreed in threads still available via Google groups (and you'll notice that Jim does not deny the allegations above).
You should have kept digging. Supercard+ was not first because I had Supercard before that. Supercard also was not first because the Shadow was before that, and the Shadow was not first because ECHO was long before that. When the Shadow failed, I was contracted by Megasoft to try to salvage it. I used my ECHO software along with a hardware jumper to 'fix' the Shadow so that it was basically my ECHO board. ECHO was created in 1984 and was the first drive RAM expansion product created and sold by a company called UnderWare, which later became Final Source Software. I knew Vic and Dave because we were distributing their PSIDAC products. ECHO was actually created as a byproduct of a board that I made for the 1541 to give me the ability to copy the 2K drive RAM into an 8K RAM, that could be moved to another memory location and examined. This is how I was able to look at drive copy protection code. I showed this modified drive (which has a digital track display that the Shadow's GT display was based on) at CommVEx a few years ago.

Keep in mind that I have always been a historical documentation freak. I have binders of documentation for every single product that I have ever created - hundreds of them. I have exact dates for prototypes, release dates, release notes, source code, etc. I even have the PCB artwork and schematics for every board. I don't have to "deny" any myths that were created by the competitors, I still have proof to this day for everything I have ever done. I will be doing a presentation on this subject at CRX in July in Las Vegas. Bruce Q. Hammond (Bryce Nesbits partner on StarDos) will be there along with Nate Lawson (who has all of SSI's documentation from their era). Come to the event and you will a great history lesson on the turn of events, who was first at what, etc.



User avatar
eslapion
Member
Member
Posts: 702
Joined: Mon Jul 20, 2015 10:11 am
Location: Canada

Re: What the %$@# is up with links from certain other forums?

Post by eslapion » Mon Mar 13, 2017 5:58 pm

JimDrew wrote:
Mon Mar 13, 2017 4:28 pm
You guys are missing the fact that the 1541/1571 disk drive outputs either 4.85v (or more, depending on actual Vcc) for a high, and .125v (or less) for a low on the address and data bus, when reading/writing data. That's it - period. There are no other voltages that are latched on the bus. Because of this, there are no possible issues. I agree if there were some marginal voltages below the acceptable thresholds, then certainly there could be a problem - but that is never going to be the case with the 1541/1571... and 28 years of boards working has definitely proved that.
Jim, let me explain something to you that seems to completely elude you.

No digital IC, logic or CPU or custom ever signals at a specific voltage. It either pulls low or pulls high using some kind of transistor, wether it be a FET or BJT. Saying a disk drive or computer or whatever equipment signals low or high at such and such voltage is utter nonsense.

The type of transistor used in NMOS ICs has been throughly described on the Denial forum in a thread related to the investigation of the insides of the 6561.

The most prolific poster is lance.ewing here: http://sleepingelephant.com/ipw-web/bul ... =11&t=7118

The datasheet for the MOS 6502 is here: http://archive.6502.org/datasheets/mos_ ... v_1985.pdf

It guaranteed logic high will be Vss+2.4 volts or higher and a logic low will be Vss+0.4 or lower. If you get a lower logic low or a higher logic high then you're just lucky and it happens because the load on the bus is lower than a certain value.
Wealth, like happiness, is never attained directly. It comes as a by-product of providing a useful service. -Harland D. Sanders

User avatar
eslapion
Member
Member
Posts: 702
Joined: Mon Jul 20, 2015 10:11 am
Location: Canada

Re: What the %$@# is up with links from certain other forums?

Post by eslapion » Mon Mar 13, 2017 7:58 pm

Continued from above...

N channel MOSFETs in the 65XX series of chip are either depletion mode or enhancement mode - they pull high or low. Those that pull low can drive a pretty good amount of current but those that pull high drive only a few hundreds of microamps. They are really designed to signal to "something" that pulls up. 74LS and other TTL logic circuits do just that, CMOS logic circuits DON'T.
You guys are missing the fact that the 1541/1571 disk drive outputs either 4.85v (or more, depending on actual Vcc) for a high, and .125v (or less) for a low on the address and data bus, when reading/writing data. That's it - period.
Did you ever check the difference between Vcc and ground on the CPU socket of that card ? SURPRISE !!! :lol: you have less than 4.5V so how could you ever get 4.85v ??
Wealth, like happiness, is never attained directly. It comes as a by-product of providing a useful service. -Harland D. Sanders

JimDrew
Member
Member
Posts: 18
Joined: Sun Jul 20, 2014 6:55 am
Location: Lake Havasu City, AZ

Re: What the %$@# is up with links from certain other forums?

Post by JimDrew » Mon Mar 13, 2017 11:22 pm

Did you ever check the difference between Vcc and ground on the CPU socket of that card ? SURPRISE !!! :lol: you have less than 4.5V so how could you ever get 4.85v ??
Surprise! That is where the voltage was measured. Vcc and ground measured either at the drive hardware or at the 6502 itself shows over 4.8v (about 4.85v). LIkewise, when you capture any of the address or data lines, the high level is also >4.8v.

I understand what you are trying to say, but the reality is that what you describe does NOT exist with the 1541/1571 hardware and the Supercard+ board. The high/low thresholds are plenty enough to meet the VIL and VOH. If this was not the case, the Supercard+ using HC type chips would simply not work - and it certainly does.

User avatar
eslapion
Member
Member
Posts: 702
Joined: Mon Jul 20, 2015 10:11 am
Location: Canada

Re: What the %$@# is up with links from certain other forums?

Post by eslapion » Tue Mar 14, 2017 2:04 am

JimDrew wrote:
Mon Mar 13, 2017 11:22 pm
Did you ever check the difference between Vcc and ground on the CPU socket of that card ? SURPRISE !!! :lol: you have less than 4.5V so how could you ever get 4.85v ??
Surprise! That is where the voltage was measured. Vcc and ground measured either at the drive hardware or at the 6502 itself shows over 4.8v (about 4.85v). LIkewise, when you capture any of the address or data lines, the high level is also >4.8v.
Yes... IF you use the ground from the power supply or the board when you check.

Your measure does not account for the fact the ground on the board is HIGHER than zero volt because of the drop across the ribbon cable.

Nonetheless, it's pure luck that there is very little load on the Address/data busses of the 1571. If done properly, your card would work with both 74LS TTL and CMOS logic ICs, assuming they are TTL compatible. It is still true the reason you cannot use 74LS chips on the Supercard+ is absolutely not because of whatever noise; it is because of mismanaged power.
Wealth, like happiness, is never attained directly. It comes as a by-product of providing a useful service. -Harland D. Sanders

JimDrew
Member
Member
Posts: 18
Joined: Sun Jul 20, 2014 6:55 am
Location: Lake Havasu City, AZ

Re: What the %$@# is up with links from certain other forums?

Post by JimDrew » Tue Mar 14, 2017 9:38 pm

I was using Vcc/ground at the Supercard+ board side for testing. I also tested from the 6502 socket side to the 6502 itself in the Supercard+ board. The voltage shift that occurs due to the cable length is insignificant, and of course all of the signals would be shifted together. There is not enough resistance in a 8" piece of cable to create a significant voltage/current drop. What can occur in a cable assembly though is ringing, and that is something that HC/HCT and other families can help minimize over LS chips. I don't consider it luck. It was just a design that just so happened to work out due to the nature of the host (1541/1571) hardware, otherwise it would have required buffer chips ('244/'245) on the address and data lines.

User avatar
eslapion
Member
Member
Posts: 702
Joined: Mon Jul 20, 2015 10:11 am
Location: Canada

Re: What the %$@# is up with links from certain other forums?

Post by eslapion » Tue Mar 14, 2017 11:38 pm

JimDrew wrote:
Tue Mar 14, 2017 9:38 pm
I was using Vcc/ground at the Supercard+ board side for testing.
The power supply in the 1571 is an early switching PSU. Some give 5.2 volts, some will give 4.85.

If your specific PSU gives close to 5.2V then you will measure 4.8V on the Supercard+.
I also tested from the 6502 socket side to the 6502 itself in the Supercard+ board. The voltage shift that occurs due to the cable length is insignificant, and of course all of the signals would be shifted together.
Did you actually measure that ? I did.
There is not enough resistance in a 8" piece of cable to create a significant voltage/current drop.
Same as above...
What can occur in a cable assembly though is ringing, and that is something that HC/HCT and other families can help minimize over LS chips.
Ringing is even more significant when you have no capacitors. There should be a 0.1uF capacitor decoupling the power for every single digital IC. Yet there are 6 ICs on the Supercard+ without a single capacitor to keep the power stable.
I don't consider it luck. It was just a design that just so happened to work out due to the nature of the host (1541/1571) hardware, otherwise it would have required buffer chips ('244/'245) on the address and data lines.
If you had used 74HCT chips and placed capacitors then and only then you could say what you did was by design - HCT chips are low power just like HC chips but they are fully compatible with the levels used by TTL ICs. Even today, you still deny the relevance of using capacitors and going for HCT instead of HC.

That's obstinacy in ignorance.

Edit: 40 lines ribbon cable were designed to send/receive IDE/ATA signals, not send more than 100mA of power... they do resist and cause voltage drop.
Wealth, like happiness, is never attained directly. It comes as a by-product of providing a useful service. -Harland D. Sanders

JimDrew
Member
Member
Posts: 18
Joined: Sun Jul 20, 2014 6:55 am
Location: Lake Havasu City, AZ

Re: What the %$@# is up with links from certain other forums?

Post by JimDrew » Thu Mar 16, 2017 9:07 pm

The power supply voltage at the 1571 motherboard connector is 4.89v. I see about 4.82v to 4.87v (it varies depending on what is going on with the bus traffic) at the 6502 socket itself, measured with a DSO.

Yep, I agree... the caps should have been there, and that was a sore subject with me. They were omitted because "it worked fine without them" and they were "too expensive". I designed the Supercard+ boards for Utilities Unlimited, but I did not produce them. Back in the day, these caps were pricey, especially the labor of hand soldering hand them in and trimming the leads. They couldn't be re-flowed like the chips/sockets. That would have added ~$6.00 to the production cost. I drove to Seattle, WA (about 180 miles away) and picked up the production sample from the assembly house and learned that the caps had been removed from the design without me knowing about it. This was the first and last time that happened. I believe that any chip (S,F, HC, HCT) except the LS worked properly, so boards were made with whatever was cheapest/available. The ONLY returns that we ever got were due to people bending pins on the 6502 header while trying to plug it into the original 6502 socket. We didn't have any actual board failures because they were all tested prior to shipping.

User avatar
Gyro Gearloose
Member
Member
Posts: 133
Joined: Sun Nov 15, 2015 5:20 am

Re: What the %$@# is up with links from certain other forums?

Post by Gyro Gearloose » Fri Mar 17, 2017 1:11 am

Image
The price one pays for pursuing any profession, or calling, is an intimate knowledge of its ugly side.

User avatar
eslapion
Member
Member
Posts: 702
Joined: Mon Jul 20, 2015 10:11 am
Location: Canada

Re: What the %$@# is up with links from certain other forums?

Post by eslapion » Fri Mar 17, 2017 3:58 am

JimDrew wrote:
Thu Mar 16, 2017 9:07 pm
... I believe that any chip (S,F, HC, HCT) except the LS worked properly, so boards were made with whatever was cheapest/available. The ONLY returns that we ever got were due to people bending pins on the 6502 header while trying to plug it into the original 6502 socket. We didn't have any actual board failures because they were all tested prior to shipping.
You were lucky.

But if the caps were removed without your knowledge then that's not your fault. Whomever decided to remove them was irresponsible.
Wealth, like happiness, is never attained directly. It comes as a by-product of providing a useful service. -Harland D. Sanders

Post Reply Previous topicNext topic