{"id":313,"date":"2022-08-30T14:59:16","date_gmt":"2022-08-30T14:59:16","guid":{"rendered":"https:\/\/unknownerror.org\/index.php\/2013\/10\/17\/problem-about-zmodem-record-and-share-programming-errors\/"},"modified":"2022-08-30T14:59:16","modified_gmt":"2022-08-30T14:59:16","slug":"problem-about-zmodem-record-and-share-programming-errors","status":"publish","type":"post","link":"https:\/\/unknownerror.org\/index.php\/2022\/08\/30\/problem-about-zmodem-record-and-share-programming-errors\/","title":{"rendered":"problem about zmodem-Record and share programming errors"},"content":{"rendered":"<ul>\n<li><img decoding=\"async\" src=\"http:\/\/www.gravatar.com\/avatar\/117c0d7cacdbd76827401b822b3037cb?s=32&amp;d=identicon&amp;r=PG\" \/><br \/>\nmattdm<br \/>\nprotocols zmodem<br \/>\nI need to include basic file-sending and file-receiving routines in my program, and it needs to be through the ZMODEM protocol. The problem is that I&#8217;m having trouble understanding the spec.For reference, here is the specification.The spec doesn&#8217;t define the various constants, so here&#8217;s a header file from Google.It seems to me like there are a lot of important things left undefined in that document:It constantly refers to ZDLE-encoding, but what is it? When exactly do I use it, and when don&#8217;t I use it? After a ZFILE data frame, the file&#8217;s metadata (filename, modify date, size, etc.) are transferred. This is followed by a ZCRCW block and then a block whose type is undefined according to the spec. The ZCRCW block allegedly contains a 16-bit CRC, but the spec doesn&#8217;t define on what data the CRC is computed. It doesn&#8217;t define the CRC polynomial it uses. I found out by chance that the CRC32 poly is the standard CRC32, but I&#8217;ve had no such luck with the CRC16 poly. Nevermind, I found it through trial and error. The CRC16 poly is 0x1021.I&#8217;ve looked around for reference code, but all I can find are unreadable, undocumented C files from the early 90s. I&#8217;ve also found this set of documents from the MSDN, but it&#8217;s painfully v<\/li>\n<\/ul>\n<p id=\"rop\"><small>Originally posted 2013-10-17 01:49:51. <\/small><\/p>","protected":false},"excerpt":{"rendered":"<p>mattdm protocols zmodem I need to include basic file-sending and file-receiving routines in my program, and it needs to be through the ZMODEM protocol. The problem is that I&#8217;m having trouble understanding the spec.For reference, here is the specification.The spec doesn&#8217;t define the various constants, so here&#8217;s a header file from Google.It seems to me [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-313","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/313","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/comments?post=313"}],"version-history":[{"count":0,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/313\/revisions"}],"wp:attachment":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/media?parent=313"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/categories?post=313"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/tags?post=313"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}