>>> On 4/29/2014 at 11:13 AM, Scott Ford <[email protected]> wrote: > Its surprising that IBM hasn't thought about using C in exits , like RACF or > other components. > > Considering Linux has been writing their Kernel in it for a few years. Not > bashing IBM, curious why they haven't embraced C in the systems arena. I see > it in some of the system type tools.
Linux was initially written in C for whatever reason (most likely ease of coding and availability of a compiler), initially. As time went on, it stayed that way for relatively easy portability to other architectures. What having an entire operating system written in C does _not_ do, however, it wring the last bit of performance out of a particular hardware platform. It's one of the reasons why z/OS and z/VM were able to perform so well on systems like the 9672 or z800/z900, but Linux performance pretty much stank. >From my perspective, it was Linux on System z that really pointed out how slow >IBM mainframes were in raw CPU power (about 200MHz) compared to other >architectures such as Power and Intel/AMD. Over time that situation has >changed radically, of course, and now System z has the fastest CPU cycle times >in the industry. But I doubt that would have happened as quickly as it did, >if it weren't for IBM's desire to continue to sell hardware to run Linux on >System z. And, if you look closely, sections of code in the kernel that are considered critical to overall system performance _are_ written in assembler for every architecture. I would say that given the fact that IBM isn't interested in porting z/OS (including RACF and the like) to other hardware platforms, they'd be insane to start coding large chunks of it in C. Mark Post ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
