<p>Re Posts #109, 111, 113</p>
<p>“UNIX was literally just introduced to Macs with Leopard…”</p>
<p>I don’t know exactly what nj<em>azn</em>premed meant when he wrote this, but it’s possible that he was alluding to the difference between UNIX and Unix-like. (I’m sure BCEagle91 is well aware of the distinction, but he didn’t explicitly state it in his post #111.)</p>
<p>Until Leopard, all releases of OS X were “Unix-like.” As you can clearly see in [this</a> pdf from Apple](<a href=“http://images.apple.com/macosx/pdf/MacOSX_UNIX_TB_v2.pdf]this”>macOS Sequoia - Apple), Tiger was described as an operating system with a “…UNIX-based” foundation (emphasis mine). It didn’t have UNIX certification, so Apple couldn’t say it was a true UNIX.</p>
<p>Leopard changed that. It was the first OS X release to be [UNIX</a> 03 certified](<a href=“http://www.opengroup.org/openbrand/register/brand3555.htm]UNIX”>Open Brand). Thus, Leopard is a true UNIX.</p>
<p>Tiger was released in April 2005. I believe that Apple tried to get it certified as a UNIX but failed for some reason. By comparison, IBM got AIX 5L [url=<a href=“http://www.opengroup.org/openbrand/register/brand3463.htm]certified[/url”>Open Brand]certified[/url</a>] in October 2004. So, if Apple didn’t try to certify Tiger, it wasn’t because they didn’t have the time to do so.</p>