Re: What is largest record that can be sent using LU2?
On Wed, 7 Oct 2009 16:39:48 -0500, Ward, Mike S mw...@ssfcu.org wrote: I tried getting LU0 to work, but couldn't. So I used LU2 and it worked. But used it to do what? What's behind the LU on the remote end? A 3270 emulator that displays the data? Or a program that does something else with the data? If the former, and if that emulator accurately emulates a 3270, you are functionally limited to sending at most the size of the screen specified in the BIND. You can send as much data as you like but there is only one buffer for the data to go into. You won't get an error; you will just overlay data. Actually, you may have a much greater limitation. It all depends on the 3270 screen addressing being used by the CICS transaction. If it were foolishly sending 100k bytes of data in 8-byte chunks all specifying the same 8-byte field in the 3270 buffer you would be functionally limited to sending 8 bytes. And if tried to use a buffer address outside the screen size the 3270 emulator will choke and give you an error. BTW, LU0 has 2 very different implications, depending on context. #1. In general, LU0 implies a roll-your-own protocol where you write the LU application at each end to do whatever you want (within the limits of SNA); you (the programmer) design your own rules and write the applications to follow those rules. #2. LU0 3270 support, which is VTAM's support for non-SNA 3270. In either case, I'm not surprised LU0 didn't work ... unless you knew that LU0 was specifically required. I was more wondering why you were using any 3270 datastream. Why not LU1? (Or even LU6.2, but that would be a lot more work.) Pat O'Keefe -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
What is largest record that can be sent using LU2?
Hello all, I have LANDP talking to windows Communications Server via LUA. Then Windows/CS talks to mainframe(CICS) via DLUR terminals using (LU2) protocol. What is the largest record that can be sent from Windows/CS using LU2 to CICS? Is there some mechanism for chaining very large records(6K) blocks together? == This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to which they are addressed. If you have received this email in error please notify the system manager. This message contains confidential information and is intended only for the individual named. If you are not the named addressee you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately by e-mail if you have received this e-mail by mistake and delete this e-mail from your system. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: What is largest record that can be sent using LU2?
Mike From a theoretical point of view, SNA can be said to impose a limit of 491 520 bytes in a request unit (RU) since that is the limit of the RU sizes byte in the BIND request, corresponding to X'FF'. However, even this field is only advisory and so a larger value could be used. If you want to indicate that the request units you are sending constitute a larger unit of data at the level of the application, you used the right SNA word to describe the mechanism, namely chain. There are two bits in the request header which are used to indicate only in chain, beginning of chain, middle in chain and end of chain with an obvious pattern of use. You could certainly send any size of data using chaining with LU type 2, whether the RU sizes were 6 x 1024 = 6 144, or any other value equal to or less than 491 520. Note that, in case you were concerned about another possible limitation, the RUs could be segmented over any intermediate data link control medium. I can't tell you what limits you may encounter in CICS or Windows/CS. If you are in charge of the programming behind each of the communicating LUs, just how large the units of data at the level of the application are will be a matter with which your programming will deal. Chris Mason On Wed, 7 Oct 2009 13:35:51 -0500, Ward, Mike S mw...@ssfcu.org wrote: Hello all, I have LANDP talking to windows Communications Server via LUA. Then Windows/CS talks to mainframe(CICS) via DLUR terminals using (LU2) protocol. What is the largest record that can be sent from Windows/CS using LU2 to CICS? Is there some mechanism for chaining very large records(6K) blocks together? -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: What is largest record that can be sent using LU2?
Thank you Chris. I actually understood what you said this time :) -Original Message- From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of Chris Mason Sent: Wednesday, October 07, 2009 2:33 PM To: IBM-MAIN@bama.ua.edu Subject: Re: What is largest record that can be sent using LU2? Mike From a theoretical point of view, SNA can be said to impose a limit of 491 520 bytes in a request unit (RU) since that is the limit of the RU sizes byte in the BIND request, corresponding to X'FF'. However, even this field is only advisory and so a larger value could be used. If you want to indicate that the request units you are sending constitute a larger unit of data at the level of the application, you used the right SNA word to describe the mechanism, namely chain. There are two bits in the request header which are used to indicate only in chain, beginning of chain, middle in chain and end of chain with an obvious pattern of use. You could certainly send any size of data using chaining with LU type 2, whether the RU sizes were 6 x 1024 = 6 144, or any other value equal to or less than 491 520. Note that, in case you were concerned about another possible limitation, the RUs could be segmented over any intermediate data link control medium. I can't tell you what limits you may encounter in CICS or Windows/CS. If you are in charge of the programming behind each of the communicating LUs, just how large the units of data at the level of the application are will be a matter with which your programming will deal. Chris Mason On Wed, 7 Oct 2009 13:35:51 -0500, Ward, Mike S mw...@ssfcu.org wrote: Hello all, I have LANDP talking to windows Communications Server via LUA. Then Windows/CS talks to mainframe(CICS) via DLUR terminals using (LU2) protocol. What is the largest record that can be sent from Windows/CS using LU2 to CICS? Is there some mechanism for chaining very large records(6K) blocks together? -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html == This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to which they are addressed. If you have received this email in error please notify the system manager. This message contains confidential information and is intended only for the individual named. If you are not the named addressee you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately by e-mail if you have received this e-mail by mistake and delete this e-mail from your system. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: What is largest record that can be sent using LU2?
On Wed, 7 Oct 2009 14:33:18 -0500, Chris Mason chrisma...@belgacom.net wrote: A minor gloss on Chris's response ... If you want to indicate that the request units you are sending constitute a larger unit of data at the level of the application, There are two bits in the request header which are used to indicate only in chain, beginning of chain, middle in chain and end of chain with an obvious pattern of use. The Large Message Performance Enhancement (which has nothing to do with performance, as far as I can see) allows a program to send an indefinitely long (I think) list of blocks of data, each up to 32k bytes long (I think). VTAM will do all the required collecting and chaining. I'd be very surprised if CICS did not use LMPE. It has been available since the early to mid 80s, and is very handy for combining independent chunks of data into one RU (chain), whether or not large applies. ... I can't tell you what limits you may encounter in CICS or Windows/CS. If you are in charge of the programming behind each of the communicating LUs, just how large the units of data at the level of the application are will be a matter with which your programming will deal. ... On the other hand, if there is something inherently 3270-ish in the Windows/CS side - something like a display buffer - be aware that data will wrap when it comes to the end of the buffer and overlay what may be at the beginning of the buffer. If there is NOT anything 3270-ish involved, why is an LU2 session being used? Please forgive me for breaking my vow of silence. I'll now return to lurkdom. Pat O'Keefe -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: What is largest record that can be sent using LU2?
I tried getting LU0 to work, but couldn't. So I used LU2 and it worked. -Original Message- From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of Patrick O'Keefe Sent: Wednesday, October 07, 2009 4:02 PM To: IBM-MAIN@bama.ua.edu Subject: Re: What is largest record that can be sent using LU2? On Wed, 7 Oct 2009 14:33:18 -0500, Chris Mason chrisma...@belgacom.net wrote: A minor gloss on Chris's response ... If you want to indicate that the request units you are sending constitute a larger unit of data at the level of the application, There are two bits in the request header which are used to indicate only in chain, beginning of chain, middle in chain and end of chain with an obvious pattern of use. The Large Message Performance Enhancement (which has nothing to do with performance, as far as I can see) allows a program to send an indefinitely long (I think) list of blocks of data, each up to 32k bytes long (I think). VTAM will do all the required collecting and chaining. I'd be very surprised if CICS did not use LMPE. It has been available since the early to mid 80s, and is very handy for combining independent chunks of data into one RU (chain), whether or not large applies. ... I can't tell you what limits you may encounter in CICS or Windows/CS. If you are in charge of the programming behind each of the communicating LUs, just how large the units of data at the level of the application are will be a matter with which your programming will deal. ... On the other hand, if there is something inherently 3270-ish in the Windows/CS side - something like a display buffer - be aware that data will wrap when it comes to the end of the buffer and overlay what may be at the beginning of the buffer. If there is NOT anything 3270-ish involved, why is an LU2 session being used? Please forgive me for breaking my vow of silence. I'll now return to lurkdom. Pat O'Keefe -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html == This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to which they are addressed. If you have received this email in error please notify the system manager. This message contains confidential information and is intended only for the individual named. If you are not the named addressee you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately by e-mail if you have received this e-mail by mistake and delete this e-mail from your system. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited. -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
