Tuesday, May 15, 2018

20 Years of USB

Accidental Tech Podcast had a good segment on the many changes that USB brought and how, amazingly, peripherals for the original iMac can still be used today. I have always seen USB as a mixed bag. For the industry as a whole, it’s certainly a success. But for a Mac user, it represents a lowest common denominator approach and a degradation of the user experience in some ways.

All wired keyboards and mice can now use the same connector, and you can plug the mouse into the keyboard. That’s great—but we had that with ADB, and ADB input devices didn’t periodically stop working and have to be unplugged and replugged.

In theory, hubs are better than daisy chaining, but finding a USB hub that’s reliable is a challenge. Even when directly connected, nearly every USB 3 storage device I’ve used is subject to spontaneous unmounting. (That never happened with SCSI.) And the availability of hubs made Apple comfortable with reducing the number of USB ports, which amongst other reasons is a problem because some USB devices don’t work with hubs.

It took until at least USB 3 before it was as fast as FireWire.

Hot swapping devices worked reliably with FireWire, but doing that with my new USB 3.1 drive dock will sometimes knock other USB devices off the bus.

It sounds convenient that USB-C and Thunderbolt 3 now share the same port, but this has brought USB’s flakiness to the formerly rock solid DisplayPort. Every month or so my iMac stops recognizing my external display until I’ve restarted a few times and plugged and replugged the connector and swapped it back and forth between the different ports. (At least I have two.)

Previously: 20 Years of iMac.

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For hackintosh users, a compatible FireWire PCI-e card (with a mix of 400 and 800 ports) is about $15 on eBay. If you get one with a Texas Instruments chipset, they usually work right out of the box.

One reason I have been advocating for something like USB - D. It needs to enforce USB Type C connector, and enforce on certain quality and speed. In the 20 years, 20 years! In many respect, Firewire is still many times better then USB.

Note that Firewire controller chips are no longer being manufactured. You might want to decommission any Firewire peripherals.

See Thom Hogan on this, he was at NAB, and :
“Here’s what I was told by multiple vendors: they simply can’t buy Firewire controllers anymore. When they run out their current stock of parts, any Firewire device they are making will have to be end-of-lifed. So those of you hoping to keep using your old Firewire drives on new and future docks for your computers, I’m sorry to dash your hopes, but it’s time to move on.”

One of the main issues with USB and especially with USB-C and TB3 is the cables.
If all (or vast majority of) the available cables were Thunderbolt 3 data, and full power compatible the confusion would be a lot lower.
Another thing that seems to be missing is the TB3 devices should fall back to USB 3 when they are connected to non-TB computer.
Plus if Apple would have at least one USB-3A port on new MBP then much of the aggravation with the new USB Type C would be marginal.

A good quality hubs (one with lots of new USB-C ports, and one with many legacy ports like Mini-Display, TB2, FW800 etc) from Apple would help too.

It's a feeling of neglect from Apple again comes to mind.

"That’s great—but we had that with ADB, and ADB input devices didn’t periodically stop working and have to be unplugged and replugged."

Yes, but ADB wasn't hot-swappable. I remember having to reboot the machine if the mouse was ever disconnected while it was on, because even after you reconnected it, you could no longer move the cursor.

Also you mention SCSI. Remember SCSI terminators? If you didn't have a terminator (which was a little do-nothing dongle) at the end of your SCSI device chain, your devices weren't even recognized. And of course, SCSI wasn't hot-swappable either, so you'd have to shut down, attach the terminator, then boot up. And the first time I ever saw a kernel panic on OS X was when I absent-mindedly disconnected a SCSI device while the machine was on, because I was so used to USB at that point.

Those were the days...

@Doodpants ADB was definitely hot-swappable. In 15 or so years of use, I never had to reboot because of an ADB issue.

I don’t understand why people are upset about SCSI termination. It’s a rule that you had to learn, but once you knew it everything worked predictably and reliably—unlike with USB.

ADB was not supposed to be hot swappable. I agree with Doodpants. Did I do it anyway on occasion? Yep. But it could technically damage the system and the device was not always recognized. As a classic Mac aficionado, I used ADB ports well into the 2000s. Like 2008, maybe even 2009ish. Probably not past 2010, as I drastically cut down my collection of classic Macs.

ADB Not Hot Swappable:

One peculiarity of ADB is that in spite of being electrically unsafe for hot-swapping on all but a few machines, it has all of the basic capabilities needed for hot-swapping implemented in its software and support hardware. On practically all original ADB systems it is not safe to plug in or unplug a device once the system is powered on (unlike modern day busses designed with hot-swap in mind). This can cause the opening of a soldered-in fuse on the motherboard. If brought to an authorised dealer, this can result in a motherboard swap at a significant expense. A simple alternative is to obtain a fuse at a nominal cost and wire it in parallel across the open motherboard fuse (not even requiring soldering if done appropriately).

USB innovations over ADB

Many ideas evolve. Apple was working on (or had at least thought of) ADB-2 -- a faster follow-on to ADB with some nicer features like more than 16-32 devices, and more power, hot swappable and so on, (and had been working on the very fast FireWire) -- but Intel copied with their revolutionary USB. Apple wisely chose to go USB because it was going to be a standard.

As far as SCSI, no, it kind of sucked. Desktop Macs not routinely adding/removing connections? Not so bad. PowerBooks? Not so great. You had to shut the computer down and make sure everything was connected properly next start up or no dice. I managed to do it, but I don't know very many Mac users who use more than maybe a single SCSI device at a time (yeah, yeah, anecdotal). I had scannners and a variety of external drives (hard, Zip, Jaz, etc.). Let's not forget the oddball 30 pin connector for PowerBooks....amongst the host of different sized ports for devices.

@Nathan That’s interesting about ADB. Apple’s documentation sounds definitive. In any case, I stand by my point that ADB input devices did not spontaneously stop working the way USB ones sometimes do.

I totally agree that SCSI was a pain. But again, if you followed the rules, it worked, whereas USB made promises that it didn’t reliably deliver upon (and FireWire did).

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