Usb - Pro/Con

From: David V. Corbin <>
Date: Wed Sep 22 18:47:38 2004

Taking it "Point by Point"...

>>> > While I do agree that USB is NOT a be-all do-all, like some
>>> > proponents, I do not think is a is *Botch* either.
>>> There is plenty I don;t like about it. Like so much of
>>> modern computing it's designed to let idiots do simple
>>> tasks trivially, but it also makes it impossible for
>>> hackers to do difficult tasks. Since I seem to always want
>>> to do the latter..
>>> I don't like the fact that you're supposed to pay for an ID
>>> (and have thr device 'certified') if you want to make your
>>> own stuff. Never had this problem with RS232 :-)

You need to pay for and get certified if you are going to make a legitimate
network appliance also [MAC ID]. Of course most products purchase a
pre-sertified module. Same if you are going to create a cellular product [I
happen to use WaveCom modules in mine].
>>> And the fact that you seem to need special drivers for many
>>> devices which you can bet are not available for any of my machines.

Although I can not find the link at presend, there is source code for low
level drivers. Since your environment (by choice) is the use of equipment
that is not currently supported, rooling your own drivers seems reasonable
to me.
>>> And the fact that it's very assymmetric (there are 'masters' and
>>> 'slaves') is something I don't like either. RS232 was much
>>> more symmetrical.

RS-232 is an ELECTRICAL Specification. The protocols that are run on
This are independand. Lets keep it apple and apples.....

Consider RS-485 (Which I use heavily for my DMX lighting). One note MUST act
as a coordinator, although they are all electrically equivilant.

>>> An example of why I don't like this. My HP100LX has an
>>> RS232 port. It was clearly designed to link it to a PC to
>>> transfer files (and it does this perfectly well). But as
>>> it's an RS232 port I can also link it directly to a serial
>>> printer, or to a modem, or...
>>> More modern palmtops have USB ports. They're slaves,
>>> designed to hang off a PC. You can't link them directly to
>>> a printer. It's interesting that some of my older handhelds
>>> have HPIL ports, but by default the handheld is the loop
>>> controller ('master'), so you can link them straight to a
>>> printer. But they can be 'slaves' if you want to link them
>>> to a larger machine. We've gone backwards (as usual)

To be honest, I have not looked into the electricals on this. I am NOT sure
that they are *REQUIRED* to be slaves.

>>> >
>>> > Any x86 style computer CAN have a usb port, and there are
>>> kits for
>>> > other
>>> I've never seen an ISA USB card...

Check out the products from SimTec. Their offerening have changed, but they
do have ISA USB Cards.

>>> > platforms as well [I integrated a USB sub-system with and
>>> embedded
>>> > ARM-7 system last year], so I am confused about your
>>> stantement that
>>> > not of the computers you have *CAN* have usb ports.
>>> All my PCs have ISA slots only. Other machines have Unibus,
>>> Qbus, BBC 1MHz bus/Torch X-bus, various custom I/O slots
>>> (like on th HP9830), HPIL, PERQlink, etc. Just about all of
>>> those have RS232 (or compatible) ports, I've nver seen USB
>>> for any of them

Again, development boards ARE out their that give you everything you need to
interface to nearly any host...

>>> > I also don't understand your statement that it is not a bus.....
>>> Electrically it's not a bus. If it was, I could just parallel up
>>> connectors and plug in several devices, there'd be no need
>>> to _always_
>>> have a hub (which, from what I've seen, contains a fair
>>> amount of logic).

By that argument (which has valid aspects), then ArcNet was not a bus
either, and RS-232 is DEFINITELY not a bus architecture (it is purely point
to point).
Received on Wed Sep 22 2004 - 18:47:38 BST

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