<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On 14 Mar 2012, at 03:44, Richard O'Keefe wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><span class="Apple-tab-span" style="white-space: pre; "> </span>You cannot make a reliable system by *extending* an<br><span class="Apple-tab-span" style="white-space: pre; "> </span>unreliable system.</span></blockquote></div><div><br></div><div>Hmm, I guess that depends on what you read into the word 'extending'.</div><div><br></div><div>Erlang processes are unreliable, but supervision structures, which build on erlang processes, are more reliable.</div><div><br></div><div>A system of erlang nodes can be more reliable than a singe node.</div><div><br></div><div>A pair of computers in a redundant configuration can be more reliable than a single computer.</div><div><br></div><div>In essense, one *always* builds reliable (complex) systems out of less reliable parts.</div><div><br></div><div>That said, Erlang has some very nice *fundamental* facilities to enable this, and adding fault-tolerance as an afterthought in other languages is likely as hard as adding strong static type checking to Erlang - that is, it can be done, and has been done to quite some extent, but those who have worked in a language where it was envisioned from the start will argue that it's a pale copy of the Real Thing.</div><div><br></div><div>BR,</div><div>Ulf W</div></body></html>