Hi Aditya

I use Mkiv both standalone and live.contextgarden.net.

Document:
\starttext
$3v$
\stoptext

Output from contextgarden and standalone attached.

log from contextgarden:
mtx-context     | run 1: luatex --fmt="/opt/context/current/tex/texmf-cache/luatex-cache/context/062e428d731d188f38ba0b7527199e92/formats/cont-en" --lua="/opt/context/current/tex/texmf-cache/luatex-cache/context/062e428d731d188f38ba0b7527199e92/formats/cont-en.lui" --backend="pdf" "./texweb.tex" \stoptext
This is LuaTeX, Version beta-0.70.1-2012052416 (rev 4277) 
 \write18 enabled.
(texweb.tex

ConTeXt  ver: 2012.05.30 11:26 MKIV  fmt: 2012.11.6  int: english/english

system          > cont-new.mkiv loaded
(/opt/context/current/tex/texmf-context/tex/context/base/cont-new.mkiv
system          > beware: some patches loaded from cont-new.mkiv
)
system          > texweb.top loaded
(texweb.top)
fonts           > latin modern fonts are not preloaded
languages       > language en is active
{/opt/context/current/tex/texmf-context/fonts/map/pdftex/context/mkiv-base.map}
fonts           > preloading latin modern fonts (second stage)
fonts           > typescripts > unknown: library 'loc'
{/opt/context/current/tex/texmf/fonts/map/dvips/lm/lm-math.map}{/opt/context/current/tex/texmf/fonts/map/dvips/lm/lm-rm.map}
fonts           > virtual math > unable to resolve name mapsfromchar
fonts           > fallback modern rm 12pt is loaded
backend         > xmp > using file '/opt/context/current/tex/texmf-context/tex/context/base/lpdf-pdx.xml'
pages           > flushing realpage 1, userpage 1
 ){/opt/context/current/tex/texmf/fonts/enc/dvips/lm/lm-mathit.enc}</opt/context/current/tex/texmf/fonts/opentype/public/lm/lmroman12-regular.otf></opt/context/current/tex/texmf/fonts/opentype/public/lm/lmroman12-regular.otf></opt/context/current/tex/texmf/fonts/type1/public/lm/lmmi12.pfb>
mkiv lua stats  > used config file          - /opt/context/current/tex/texmf/web2c/texmfcnf.lua
mkiv lua stats  > used cache path           - readable: '/opt/context/current/tex/texmf-cache/luatex-cache/context/062e428d731d188f38ba0b7527199e92' (order 1)
mkiv lua stats  > used cache path           - readable: '/tmp/texweb/luatex-cache/context/062e428d731d188f38ba0b7527199e92' (order 2)
mkiv lua stats  > used cache path           - writable: '/tmp/texweb/luatex-cache/context/062e428d731d188f38ba0b7527199e92'
mkiv lua stats  > resource resolver         - loadtime 0.010 seconds, 0 scans with scantime 0.000 seconds, 0 shared scans, 47 found files, scanned paths: 
mkiv lua stats  > stored bytecode data      - 303 modules, 65 tables, 368 chunks
mkiv lua stats  > cleaned up reserved nodes - 39 nodes, 9 lists of 438
mkiv lua stats  > node memory usage         - 2 glue, 2 penalty, 9 attribute, 29 glue_spec, 3 attribute_list
mkiv lua stats  > node list callback tasks  - 6 unique task lists, 6 instances (re)created, 134 calls
mkiv lua stats  > used backend              - pdf (backend for directly generating pdf output)
mkiv lua stats  > loaded patterns           - en::2
mkiv lua stats  > jobdata time              - 0.001 seconds saving, 0.000 seconds loading
mkiv lua stats  > callbacks                 - 263 direct, 558 indirect, 821 total
mkiv lua stats  > lxml preparation time     - 0.000 seconds, 0 nodes, 11 lpath calls, 0 cached calls
mkiv lua stats  > result saved in file      - texweb.pdf
mkiv lua stats  > loaded fonts              - 33 files: stmary10.afm lmmono12-regular.otf lmmono8-regular.otf lmmono9-regular.otf lmroman12-bold.otf lmroman12-regular.otf lmroman7-bold.otf lmroman7-regular.otf lmroman9-bold.otf lmroman9-regular.otf lmsans12-regular.otf lmsans8-regular.otf lmsans9-regular.otf eufb10.tfm eufb7.tfm eufm10.tfm eufm7.tfm msam10.tfm msam7.tfm msbm10.tfm msbm7.tfm lmex10.tfm lmmi12.tfm lmmi7.tfm lmmi9.tfm lmmib10.tfm lmmib7.tfm lmsy10.tfm lmsy7.tfm lmsy9.tfm rm-lmr12.tfm rm-lmr7.tfm rm-lmr9.tfm
mkiv lua stats  > fonts load time           - 0.291 seconds 
mkiv lua stats  > luatex banner             - this is luatex, version beta-0.70.1-2012052416 (rev 4277)
mkiv lua stats  > control sequences         - 33665 of 65536 + 100000
mkiv lua stats  > current memory usage      - 30 MB (ctx: 31 MB)
mkiv lua stats  > runtime                   - 0.805 seconds, 1 processed pages, 1 shipped pages, 1.242 pages/second
Log from standalone:
(/home/christian/context/tex/texmf-context/tex/context/base/cont-yes.mkiv

ConTeXt  ver: 2013.06.10 22:51 MKIV beta  fmt: 2013.6.13  int: english/english

system          > 'cont-new.mkiv' loaded
(/home/christian/context/tex/texmf-context/tex/context/base/cont-new.mkiv)
system          > files > jobname 'tmp', input './tmp', result 'tmp'
fonts           > latin modern fonts are not preloaded
languages       > language 'en' is active
(/tmp/latexila-X3AGYW/tmp.tex{/home/christian/context/tex/texmf-context/fonts/map/pdftex/context/mkiv-base.map}
fonts           > preloading latin modern fonts (second stage)
fonts           > typescripts > unknown library 'loc'
{/home/christian/context/tex/texmf/fonts/map/dvips/lm/lm-math.map}{/home/christian/context/tex/texmf/fonts/map/dvips/lm/lm-rm.map}
fonts           > 'fallback modern rm 12pt' is loaded
backend         > xmp > using file '/home/christian/context/tex/texmf-context/tex/context/base/lpdf-pdx.xml'
pages           > flushing realpage 1, userpage 1
 ) )</home/christian/context/tex/texmf/fonts/opentype/public/lm-math/latinmodern-math.otf></home/christian/context/tex/texmf/fonts/opentype/public/lm/lmroman12-regular.otf>

system          > files > start used files

used files      >    1: filename=cont-yes.mkiv filetype=tex foundname=/home/christian/context/tex/texmf-context/tex/context/base/cont-yes.mkiv usedmethod=database
used files      >    2: filename=cont-new.mkiv filetype=tex foundname=/home/christian/context/tex/texmf-context/tex/context/base/cont-new.mkiv usedmethod=database
used files      >    3: filename=lang-us.lua filetype=lua foundname=/home/christian/context/tex/texmf-context/tex/context/patterns/lang-us.lua usedmethod=database
used files      >    4: filename=/tmp/latexila-X3AGYW/tmp.tex foundname=/tmp/latexila-X3AGYW/tmp.tex usedmethod=direct
used files      >    5: filename=mkiv-base.map filetype=map format=map foundname=/home/christian/context/tex/texmf-context/fonts/map/pdftex/context/mkiv-base.map usedmethod=database
used files      >    6: filename=lm.lfg filetype=tex foundname=/home/christian/context/tex/texmf-context/tex/context/fonts/lm.lfg usedmethod=database
used files      >    7: filename=lm-math.lfg filetype=tex foundname=/home/christian/context/tex/texmf-context/tex/context/fonts/lm-math.lfg usedmethod=database
used files      >    8: filename=lm-math.map filetype=map format=map foundname=/home/christian/context/tex/texmf/fonts/map/dvips/lm/lm-math.map usedmethod=database
used files      >    9: filename=lm-rm.map filetype=map format=map foundname=/home/christian/context/tex/texmf/fonts/map/dvips/lm/lm-rm.map usedmethod=database
used files      >   10: filename=lmroman12-regular filetype=otf format=otf foundname=/home/christian/context/tex/texmf/fonts/opentype/public/lm/lmroman12-regular.otf usedmethod=database
used files      >   11: filename=latinmodern-math.otf filetype=opentypefonts foundname=/home/christian/context/tex/texmf/fonts/opentype/public/lm-math/latinmodern-math.otf usedmethod=database
used files      >   12: filename=latinmodern-math.otf filetype=otf format=otf foundname=/home/christian/context/tex/texmf/fonts/opentype/public/lm-math/latinmodern-math.otf usedmethod=database
used files      >   13: filename=lpdf-pdx.xml filetype=tex foundname=/home/christian/context/tex/texmf-context/tex/context/base/lpdf-pdx.xml usedmethod=database

system          > files > stop used files


system          > structure > start used structure

used structure  > text: tmp

system          > structure > stop used structure


system          > files > start used files

used file       >    1: filename=cont-yes.mkiv filetype=tex foundname=/home/christian/context/tex/texmf-context/tex/context/base/cont-yes.mkiv usedmethod=database
used file       >    2: filename=cont-new.mkiv filetype=tex foundname=/home/christian/context/tex/texmf-context/tex/context/base/cont-new.mkiv usedmethod=database
used file       >    3: filename=lang-us.lua filetype=lua foundname=/home/christian/context/tex/texmf-context/tex/context/patterns/lang-us.lua usedmethod=database
used file       >    4: filename=/tmp/latexila-X3AGYW/tmp.tex foundname=/tmp/latexila-X3AGYW/tmp.tex usedmethod=direct
used file       >    5: filename=mkiv-base.map filetype=map format=map foundname=/home/christian/context/tex/texmf-context/fonts/map/pdftex/context/mkiv-base.map usedmethod=database
used file       >    6: filename=lm.lfg filetype=tex foundname=/home/christian/context/tex/texmf-context/tex/context/fonts/lm.lfg usedmethod=database
used file       >    7: filename=lm-math.lfg filetype=tex foundname=/home/christian/context/tex/texmf-context/tex/context/fonts/lm-math.lfg usedmethod=database
used file       >    8: filename=lm-math.map filetype=map format=map foundname=/home/christian/context/tex/texmf/fonts/map/dvips/lm/lm-math.map usedmethod=database
used file       >    9: filename=lm-rm.map filetype=map format=map foundname=/home/christian/context/tex/texmf/fonts/map/dvips/lm/lm-rm.map usedmethod=database
used file       >   10: filename=lmroman12-regular filetype=otf format=otf foundname=/home/christian/context/tex/texmf/fonts/opentype/public/lm/lmroman12-regular.otf usedmethod=database
used file       >   11: filename=latinmodern-math.otf filetype=opentypefonts foundname=/home/christian/context/tex/texmf/fonts/opentype/public/lm-math/latinmodern-math.otf usedmethod=database
used file       >   12: filename=latinmodern-math.otf filetype=otf format=otf foundname=/home/christian/context/tex/texmf/fonts/opentype/public/lm-math/latinmodern-math.otf usedmethod=database
used file       >   13: filename=lpdf-pdx.xml filetype=tex foundname=/home/christian/context/tex/texmf-context/tex/context/base/lpdf-pdx.xml usedmethod=database

system          > files > stop used files


system          > options > start commandline options

used option     > currentrun="1"
used option     > fulljobname="./tmp.tex"
used option     > input="./tmp.tex"
used option     > kindofrun="1"
used option     > maxnofruns="8"
used option     > no-parse-first-line="true"

system          > options > stop commandline options

system          > options > start commandline files

used file       >    1: ./tmp.tex

system          > options > stop commandline files



mkiv lua stats  > used config file: selfautoparent:/texmf/web2c/texmfcnf.lua
mkiv lua stats  > used cache path: /home/christian/context/tex/texmf-cache/luatex-cache/context/5fe67e0bfe781ce0dde776fb1556f32e
mkiv lua stats  > resource resolver: loadtime 0.006 seconds, 0 scans with scantime 0.000 seconds, 0 shared scans, 13 found files, scanned paths: <none>
mkiv lua stats  > stored bytecode data: 330 modules (0.120 sec), 69 tables (0.000 sec), 399 chunks (0.120 sec)
mkiv lua stats  > cleaned up reserved nodes: 41 nodes, 9 lists of 441
mkiv lua stats  > node memory usage: 2 glue, 2 penalty, 9 attribute, 28 glue_spec, 3 attribute_list
mkiv lua stats  > node list callback tasks: 6 unique task lists, 6 instances (re)created, 39 calls
mkiv lua stats  > used backend: pdf (backend for directly generating pdf output)
mkiv lua stats  > loaded patterns: en::2, load time: 0.000
mkiv lua stats  > jobdata time: 0.001 seconds saving, 0.001 seconds loading
mkiv lua stats  > callbacks: 137 direct, 180 indirect, 317 total
mkiv lua stats  > randomizer: resumed with value 0.42518211455326
mkiv lua stats  > lxml preparation time: 0.000 seconds, 0 nodes, 15 lpath calls, 0 cached calls
mkiv lua stats  > result saved in file: tmp.pdf, compresslevel 3, objectcompreslevel 3
mkiv lua stats  > loaded fonts: 2 files: latinmodern-math.otf (experimental), lmroman12-regular.otf
mkiv lua stats  > fonts load time: 0.142 seconds 
mkiv lua stats  > luatex banner: this is luatex, version beta-0.76.0-2013040516  (tex live 2013/dev)(rev 4627)
mkiv lua stats  > control sequences: 37409 of 65536 + 100000
mkiv lua stats  > current memory usage: 45 MB (ctx: 45 MB)
mkiv lua stats  > runtime: 0.409 seconds, 1 processed pages, 1 shipped pages, 2.445 pages/second


2013/6/17 Aditya Mahajan <adityam@umich.edu>
On 2013-06-17, at 12:05 PM, Christian Prim <christian.prim@gmx.ch> wrote:

Hi list

rendering a very easy formula with greek text in it produces a pdf-document that has not  a valid utf-8 string.

I use evince for displaying pdfs under ubuntu linux. The document appears correctly on the screen but stops printing after a greek letter in a formula.

The error-report says:
Internal Error: cairo context error: input string not valid UTF-8

How are you compiling the document (mkii or mkiv) Can you attach the actual PDF as well (small attachments are allowed on the list). 



The same document compiled in live.contextgarden.net doesn't produce a mistake and can be printed with evince.

contextgarden uses Mkii rather than Mkiv

Aditya 

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