xmodem on 3b2 gets short blocks starting at block 16

by Jeffrey B. McGou » Sun, 04 Nov 1990 01:34:59

I recently setup xmodem on our 3B2/600 SVR3.2.

When downloading at any speed greater than 2400 baud
I start getting short blocks starting at block 16...

I have tried two different versions of xmodem...

Any help would be appreciated
thanks,
--
Lator, Don't ask me what I think of you...
Cuz I might not tell you what you want me to.
Jeffrey B. McGough

Top

1. Non blocking socket blocks; says 'read would block' ?

Hi all,

I have three sockets in server which I am reading in a continuous loop,
so don't want to wait on any one. I have designated them as 'non blocking'
but when run the server exits on the very first read() and says 'would
block'. (Is it the same as 'EWOULDBLOCK' mentioned in R. Steven's book ?)
I don't want that I should get any error msg and exit, in fact the
whole purpose of nonblocking is that if something is available, read it
else proceed in the loop and come back to read next time.
The client (sender) is sending msgs on all three sockets. The sockets
are conn_oriented. I am using SunOS 4.1. The small code part is below:

int emer_s, env_s, sens_s; /* socket fds */
//----------- making sockets nonblocking ******
if ((res=fcntl(emer_s,F_SETFL,FNDELAY)) < 0)
{
perror("fcntl res = -1");
exit(1);
}
if ((res=fcntl(env_s,F_SETFL,FNDELAY)) < 0)
{
perror("fcntl res = -1");
exit(1);
}
if ((res=fcntl(sens_s,F_SETFL,FNDELAY)) < 0)
{
perror("fcntl res = -1");
exit(1);
}

for(; ;)
{

if ((cc=read(emer_s,(char*)&gen_struct,size)) < size)
{
perror("read error");
exit(1);
}
......... do something
if ((cc=read(env_s,(char*)&gen_struct,size)) < size)
{
perror("read error");
exit(1);
}
......... do something
if ((cc=read(sens_s,(char*)&gen_struct,size)) < size)
{
perror("read error");
exit(1);
}
......... do something