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3 megabit ethernet
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glen herrmannsfeldt
Mar 31, 2015, 2:03:55 PM3/31/15
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Does anyone here know about 3 megabit ethernet?
Do any such chips still exist?
Or maybe an FPGA based bridge to 10 megabit would be the easiest
way to do the conversion.
-- glen
Do any such chips still exist?
Or maybe an FPGA based bridge to 10 megabit would be the easiest
way to do the conversion.
-- glen
Moe Trin
Mar 31, 2015, 11:56:10 PM3/31/15
to
On Tue, 31 Mar 2015, in the Usenet newsgroup comp.dcom.lans.ethernet, in article
<mfeni8$cl4$1...@speranza.aioe.org>, glen herrmannsfeldt wrote:
>Does anyone here know about 3 megabit ethernet?
Haven't seen any since.... 1996?
<mfeni8$cl4$1...@speranza.aioe.org>, glen herrmannsfeldt wrote:
>Does anyone here know about 3 megabit ethernet?
>Do any such chips still exist?
hell!
I haven't seen (Motorola) 10000 series ECL chips for sale in YEARS, but
I honestly can't recall if they were used in the 3 MHz version or just
10Base5 reference implementations. Given we're talking 1976, I vaguely
recall most of the circuit was discretes. Hey, at least it wasn't
vacuum tubes.
>Or maybe an FPGA based bridge to 10 megabit would be the easiest
>way to do the conversion.
of 8" floppies as well as several boxes of 5.25s).
Old guy
glen herrmannsfeldt
Apr 1, 2015, 12:44:58 AM4/1/15
to
Moe Trin <ibup...@painkiller.example.tld.invalid> wrote:
> On Tue, 31 Mar 2015, in the Usenet newsgroup comp.dcom.lans.ethernet, in article
> <mfeni8$cl4$1...@speranza.aioe.org>, glen herrmannsfeldt wrote:
>>Does anyone here know about 3 megabit ethernet?
> Haven't seen any since.... 1996?
>>Do any such chips still exist?
> It's getting AWFULLY close to the first of the month... but what the
> hell!
No, it is actually for an Alto.
> On Tue, 31 Mar 2015, in the Usenet newsgroup comp.dcom.lans.ethernet, in article
> <mfeni8$cl4$1...@speranza.aioe.org>, glen herrmannsfeldt wrote:
>>Does anyone here know about 3 megabit ethernet?
> Haven't seen any since.... 1996?
>>Do any such chips still exist?
> It's getting AWFULLY close to the first of the month... but what the
> hell!
> I haven't seen (Motorola) 10000 series ECL chips for sale in YEARS, but
> I honestly can't recall if they were used in the 3 MHz version or just
> 10Base5 reference implementations. Given we're talking 1976, I vaguely
> recall most of the circuit was discretes. Hey, at least it wasn't
> vacuum tubes.
>>Or maybe an FPGA based bridge to 10 megabit would be the easiest
>>way to do the conversion.
> Why? Sneaker-net would be faster to implement. (yes, I do have a box
> of 8" floppies as well as several boxes of 5.25s).
-- glen
Moe Trin
Apr 1, 2015, 4:47:11 PM4/1/15
to
On Wed, 1 Apr 2015, in the Usenet newsgroup comp.dcom.lans.ethernet, in article
<mfft47$r42$1...@speranza.aioe.org>, glen herrmannsfeldt wrote:
"ordinary" 74 series TTL. The 74164 (S->P) and 74165 (P->S) were 8 bit
parallel shift-registers. The line driver and receiver were discretes.
>>> Or maybe an FPGA based bridge to 10 megabit would be the easiest
>>> way to do the conversion.
What are you actually trying to do?
>> Why? Sneaker-net would be faster to implement. (yes, I do have a
>> box of 8" floppies as well as several boxes of 5.25s).
>I think they don't have floppy drives on them.
Alto - correct, the hard disk cartridges were removable. I was thinking
of the more "modern" DLion, which did have an 8 inch drive. We had a
number of them, and at least one had both 10 and 3 MHz interfaces, which
was used as a limited capability router.
Old guy
<mfft47$r42$1...@speranza.aioe.org>, glen herrmannsfeldt wrote:
> Moe Trin <ibup...@painkiller.example.tld.invalid> wrote:
>> glen herrmannsfeldt wrote:
>>> Does anyone here know about 3 megabit ethernet?
>> Haven't seen any since.... 1996?
>>>Do any such chips still exist?
>> It's getting AWFULLY close to the first of the month... but what the
>> hell!
>No, it is actually for an Alto.
Never worked on one, but my understanding was that the chips used were
>> glen herrmannsfeldt wrote:
>>> Does anyone here know about 3 megabit ethernet?
>> Haven't seen any since.... 1996?
>>>Do any such chips still exist?
>> It's getting AWFULLY close to the first of the month... but what the
>> hell!
>No, it is actually for an Alto.
"ordinary" 74 series TTL. The 74164 (S->P) and 74165 (P->S) were 8 bit
parallel shift-registers. The line driver and receiver were discretes.
>>> Or maybe an FPGA based bridge to 10 megabit would be the easiest
>>> way to do the conversion.
>> Why? Sneaker-net would be faster to implement. (yes, I do have a
>> box of 8" floppies as well as several boxes of 5.25s).
>I think they don't have floppy drives on them.
of the more "modern" DLion, which did have an 8 inch drive. We had a
number of them, and at least one had both 10 and 3 MHz interfaces, which
was used as a limited capability router.
Old guy
glen herrmannsfeldt
Apr 1, 2015, 6:09:02 PM4/1/15
to
Moe Trin <ibup...@painkiller.example.tld.invalid> wrote:
> On Wed, 1 Apr 2015, in the Usenet newsgroup comp.dcom.lans.ethernet, in article
(snip, I wrote)
> On Wed, 1 Apr 2015, in the Usenet newsgroup comp.dcom.lans.ethernet, in article
>>>> Does anyone here know about 3 megabit ethernet?
>>> Haven't seen any since.... 1996?
>>No, it is actually for an Alto.
> Never worked on one, but my understanding was that the chips used were
> "ordinary" 74 series TTL. The 74164 (S->P) and 74165 (P->S) were 8 bit
> parallel shift-registers. The line driver and receiver were discretes.
>>>> Or maybe an FPGA based bridge to 10 megabit would be the easiest
>>>> way to do the conversion.
> What are you actually trying to do?
Someone else is actually trying to do it, which is connect an Alto
> Never worked on one, but my understanding was that the chips used were
> "ordinary" 74 series TTL. The 74164 (S->P) and 74165 (P->S) were 8 bit
> parallel shift-registers. The line driver and receiver were discretes.
>>>> Or maybe an FPGA based bridge to 10 megabit would be the easiest
>>>> way to do the conversion.
> What are you actually trying to do?
to modern ethernet. I believe the reason is to use it for network
based disk storage.
One possibility would be to create a bridge between 3Mb and 10Mb
ethernet. Another would be to adapt a 10Mb to the Alto I/O bus,
such that it could talk to it like it was 3Mb. (Yes, I know that 3Mb
has 8 bit addresses.)
Thanks.
-- glen
Moe Trin
Apr 2, 2015, 8:47:07 PM4/2/15
to
On Wed, 1 Apr 2015, in the Usenet newsgroup comp.dcom.lans.ethernet, in article
<mfhq9s$haq$1...@speranza.aioe.org>, glen herrmannsfeldt wrote:
>Moe Trin <ibup...@painkiller.example.tld.invalid> wrote:
>Moe Trin <ibup...@painkiller.example.tld.invalid> wrote:
>> What are you actually trying to do?
>Someone else is actually trying to do it, which is connect an Alto
>to modern ethernet.
Didn't think there were any outside of museums
>Someone else is actually trying to do it, which is connect an Alto
>to modern ethernet.
>I believe the reason is to use it for network based disk storage.
Alto - the other way 'round makes no sense, as the Alto disks were
something like two or three megabytes.
>One possibility would be to create a bridge between 3Mb and 10Mb
>ethernet.
>Another would be to adapt a 10Mb to the Alto I/O bus, such that it
>could talk to it like it was 3Mb.
CPU bandwidth limited - and can't service interrupts much faster than the
3 Mb demanded.
>(Yes, I know that 3Mb has 8 bit addresses.)
Old guy
glen herrmannsfeldt
Apr 2, 2015, 9:03:10 PM4/2/15
to
Moe Trin <ibup...@painkiller.example.tld.invalid> wrote:
(snip, I wrote)
>>I believe the reason is to use it for network based disk storage.
> I'd assume you mean having an outside box act as a network disk for the
> Alto - the other way 'round makes no sense, as the Alto disks were
> something like two or three megabytes.
Yes.
I don't know the details, but it seems that the disks don't
work very well.
>>One possibility would be to create a bridge between 3Mb and 10Mb
>>ethernet.
> about the only solution
Well, it could also be a router. There probably won't be much else
on the net, so it probably doesn't matter much either way.
>>Another would be to adapt a 10Mb to the Alto I/O bus, such that it
>>could talk to it like it was 3Mb.
> Never worked on the hardware, but my impression is that the interface was
> CPU bandwidth limited - and can't service interrupts much faster than the
> 3 Mb demanded.
That is fine. At some point, most devices couldn't handle interrupts
as fast as 10Mb/s ethernet could generate them, but most of the time
they didn't have to.
>>(Yes, I know that 3Mb has 8 bit addresses.)
> The bridge device (actually a gateway) handles that.
Yes.
I just put that in, in case someone thought about mentioning it.
-- glen
(snip, I wrote)
>>Someone else is actually trying to do it, which is connect an Alto
>>to modern ethernet.
> Didn't think there were any outside of museums
It is in a museum, but it is supposed to work.
>>to modern ethernet.
> Didn't think there were any outside of museums
>>I believe the reason is to use it for network based disk storage.
> I'd assume you mean having an outside box act as a network disk for the
> Alto - the other way 'round makes no sense, as the Alto disks were
> something like two or three megabytes.
I don't know the details, but it seems that the disks don't
work very well.
>>One possibility would be to create a bridge between 3Mb and 10Mb
>>ethernet.
> about the only solution
on the net, so it probably doesn't matter much either way.
>>Another would be to adapt a 10Mb to the Alto I/O bus, such that it
>>could talk to it like it was 3Mb.
> Never worked on the hardware, but my impression is that the interface was
> CPU bandwidth limited - and can't service interrupts much faster than the
> 3 Mb demanded.
as fast as 10Mb/s ethernet could generate them, but most of the time
they didn't have to.
>>(Yes, I know that 3Mb has 8 bit addresses.)
> The bridge device (actually a gateway) handles that.
I just put that in, in case someone thought about mentioning it.
-- glen
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