Hi
Please point me to a 16-bit GPL'ed open source TCP/IP stack. I
need to use during the 16-bit real mode during pre-boot environment.

Does any one know if there are any current linux(uClinux, eCOS ,
RTlinux etc) tcp/ip stacks which can be used in 16-bit real mode.

Anyone's prior experience with using a 16-bit tcp/ip stack.

thanks for your
-vikas

What do you mean by 16-bit TCP?

TCP doesn't care about native machine bit sizes and instruction sizes.

Some code may be written that assumes 32-bit integer math is cheap.
But that's usually just the checksum routine -- easy to change.

Craig


"vik.reck@gmail.com" <vik.reck@gmail.com> writes:

>Hi
> Please point me to a 16-bit GPL'ed open source TCP/IP stack. I
>need to use during the 16-bit real mode during pre-boot environment.

>Does any one know if there are any current linux(uClinux, eCOS ,
>RTlinux etc) tcp/ip stacks which can be used in 16-bit real mode.

>Anyone's prior experience with using a 16-bit tcp/ip stack.

>thanks for your
>-vikas

In article <dv7s65$dvt$1@pcls4.std.com>,
Craig Partridge <craigp@std.com> top-posted, now corrected:
>"vik.reck@gmail.com" <vik.reck@gmail.com> writes:

>>Does any one know if there are any current linux(uClinux, eCOS ,
>>RTlinux etc) tcp/ip stacks which can be used in 16-bit real mode.

>What do you mean by 16-bit TCP?

>TCP doesn't care about native machine bit sizes and instruction sizes.

On the other hand if you have a processor with a 16-bit
non-memory-mapped address space, then you are going to have to be
careful about window sizes and fragmentation reassembly and other
items that assume that you have 64K objects readily available.

roberson@hushmail.com (Walter Roberson) writes:

>>TCP doesn't care about native machine bit sizes and instruction sizes.

>On the other hand if you have a processor with a 16-bit
>non-memory-mapped address space, then you are going to have to be
>careful about window sizes and fragmentation reassembly and other
>items that assume that you have 64K objects readily available.

TCP doesn't assume that. After all, some of the first implementations
were done on 16-bit native machines.

I just did a quick check (so I may have missed something) but the window
size is 16 bits, as is the urgent pointer. Sequence numbers are 32-bits
so you need to do some 32-bit arithmetic, but not much and it isn't
very hard. The maximum packet size is 16 bits, so you're safe there.

Certainly you don't, say, want to negotiate TCP big windows or extended
sequence numbers -- but in a 16-bit machine, you're hardly ready to accept
that kind of firehose of data anyway.

Craig

> Please point me to a 16-bit GPL'ed open source TCP/IP stack. I
>need to use during the 16-bit real mode during pre-boot environment.

IMHO your best bet is to look for "embeddable TCP" stacks. There are a
few open source projects in this area and they should be easily
portable to 16 bit real mode PC envireonement.

LwIP comes to mind, but there are others. Once you find one, links
found on such a page most likely will lead you to the others.

HTH

Markus

In article <dv92i6$otg$1@pcls4.std.com>,
Craig Partridge <craigp@std.com> wrote:

>>items that assume that you have 64K objects readily available.
>
>TCP doesn't assume that. After all, some of the first implementations
>were done on 16-bit native machines.

The trouble is not in the assumptions of protocol but the assumptions
of the implementors. Recall the recent talk here about TCP
implementations that go (or went?) crazy when presented with
"negative" port numbers and window sizes. I agree that a new TCP
implementation for a 16-bit system would not be hard write. Such
an extremely tiny system (by modern standards) should omit many
modern elaborations from header predicting to large windows to varys
buffering systems such as "cluster mbufs." The problem is that a
very tiny (by today's standards) 16-bit system is not likely to be
written from scratch instead of created by trimming and recompiling
existing code that assumes that int's contain at least 32 bits.


Vernon Schryver vjs@rhyolite.com

In article <1142277506.265880.50490@j52g2000cwj.googlegroups. com>,
vik.reck@gmail.com <vik.reck@gmail.com> wrote:
>Hi
> Please point me to a 16-bit GPL'ed open source TCP/IP stack. I
>need to use during the 16-bit real mode during pre-boot environment.
>
>Does any one know if there are any current linux(uClinux, eCOS ,
>RTlinux etc) tcp/ip stacks which can be used in 16-bit real mode.
>
>Anyone's prior experience with using a 16-bit tcp/ip stack.
>
>thanks for your
>-vikas
>

Open Source DOS probably has a real mode IP stack. I don't know
what the usage license is.

http://www.freedos.org/

--
a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.

Another open source implementation of tcp/ip protocol stack:
http://freshmeat.net/projects/uip/

>very tiny (by today's standards) 16-bit system is not likely to be
>written from scratch instead of created by trimming and recompiling
>existing code that assumes that int's contain at least 32 bits.

That's why I sugested to look in the embedded area. There, all stacks
known to me (including the one I wrote) were written from scratch.

Markus