Talk:Coherent (operating system)

message: The article says Coherent could run on "most" x86 CPUs, and starts the list at the 286.
I know, for a certain fact, that the original 1984 Coherent ran on plain old waity-waity-eights.  --  Geo Swan 13:39, 28 July 2005 (UTC)
thread_title: [untitled]

message: Being a firm believer that more information is better than less I offer my perspective. I was a heavy Coherent user between 1993 and 1995 and did some development on the platform. 
Coherent already had one foot in the grave between 1994 and 1995 when Linux began to be popular. There were two problems, a bug that started to bleed off customers slowly and a missing feature which dropped Coherent from consideration for anyone doing new development.
The first problem was the introduction of a disasterous bug in the ide disk driver. At that time many Coherent users were looking for an inexpensive means of having a UUCP news feed. If I recall correctly C-News was part of one of the CohWare packs. The genesis of the bug was the addition of multi-sector reads to the "at" driver which was done as a performance boost. The new code did not do robust error checking. The problem manifested itself when one block of a multisector transfer failed. Rather than invalidating the whole transfer the code improperly scribbled on the next few active blocks in the buffer cache. This resulted in data corruption of the buffer cache and eventually the disk. Eventually the kernel would read a plain data block when it was looking for either a directory or a part of the on-disk inode table. At that time the kernel would panic and depending on your disk i/o load fsck had very little chance of repairing your filesystem. People using Coherent for their news feeds on MFM/RLL/IDE disks were hardest hit by these problems and complained very loudly in the newsgroup. It took Mark Williams a long time to fix this problem and while it was being fixed many users migrated to Linux.
The second problem and the single largest missing feature was TCP/IP networking. Hindsight being 20-20, the decision to port X windows before adding networking to Coherent was the genesis. The dedication of resources to both build a BSD socket API and then port a very green XFree86 stole valuable development and support time from the project of getting TCP/IP networking added to the kernel. Between 1994 and 1995 the Mark Williams staff included no more than 15 developers. Had the decision been made to do TCP/IP networking first, the effort needed to build a version of the BSD sockets API would have been paid for as part of networking project and the XFree86 port would have been considerably easier both because it was on a more "standard" platform and because the XFree86 code would have been considerably more mature. Adding networking would have allowed Coherent to take part in the TCP/IP revolution that began to sweep through the computing industry in 1995. Without TCP/IP Coherent was left in the dust as Linux, *BSD and even Microsoft hopped on the runaway train that we now call the internet.
I don't know if timely attention to the "at" driver bug and networking could have saved Coherent. However, it is my guess that those two factors would have kept Coherent viable in the market until the people could buy Red Hat Linux. At the time Coherent was the cheapest choice in the closed source PC Unix market place. Also at that time Linux and BSD were radical choices and espousing their merits got you shunned inside of corporations where the big wheels needed the comfort factor of having someone to call if the system broke at 0400. 
24.44.29.247 18:29, 18 December 2006 (UTC)
thread_title:  One foot in the grave... 

message: I could provide a scan or a picture of the Coherent handbook cover, if there is some interest for it - got it laying around here (no idea though wich version). Don't know if that's a bit overkill for this article...
Sir diddymus (talk) 09:37, 24 December 2007 (UTC)
thread_title:  Image of Coherent handbook cover 

message: The article says "The manual was entirely written by Fred Butzen and was praised because of its quality".  In fact, I wrote much of the manual in the mid-1980s. Jhobson1 (talk) 16:22, 10 August 2010 (UTC)
thread_title:  Fred Butzen didn't do it alone 

message: Is there any evidence, that Coherent is BSD? If not, please remove category "Berkeley Software Distribution". If yes, please add references to sources, which prove that.
--Uniwersalista (talk) 15:43, 29 July 2013 (UTC)
replies: text: Fixed! Letdorf (talk) 19:41, 29 July 2013 (UTC)
thread_title:  BSD