diff --git a/README.md b/README.md
index d123007..89ad703 100644
--- a/README.md
+++ b/README.md
@@ -8,6 +8,9 @@ as the files 0*.pdf. We now need to convert these to machine-readable
 assembly code, write tools such as an assembler, a filesystem creation tool,
 and write from scratch missing things like a shell, ls etc.
 
+The code in the original scans are (c) Novell who own the rights to the Unix
+source code. Everything that didn't come from the scanned pages are GPLv3.
+
 scans	  holds the unmodified OCR versions of the scanned files
 
 src/cmd   holds the modified source code of the user-mode programs
diff --git a/scans/Readme b/scans/Readme
index 2447909..98da674 100644
--- a/scans/Readme
+++ b/scans/Readme
@@ -2,6 +2,9 @@ This area contains the OCR'd versions of the PDP-7 scans that are at
 http://www.tuhs.org/Archive/PDP-11/Distributions/research/McIlroy_v0/0*.pdf
 The files should be unaltered versions of the scanned pages.
 
+Novell owns the rights to the Unix source code, so these files are probably
+(c) 1970 Novell. They are certainly not under the GPLv3 license.
+
 For modified versions of these files, look in src/cmds and src/sys.
 
 Details of the files:
@@ -24,8 +27,18 @@ trysys.s: page 65  of 01-s1.pdf
 bc.s:  pages 7-11  of 06-5-12.pdf
 bi.s:  pages 12-19 of 06-5-12.pdf
 bl.s:  pages 3-6   of 06-5-12.pdf
+cat.s: pages 21-23 of 06-5-12.pdf
+
+db.s:     pages 2-21  of 07-13-19.pdf
+dmabs.s:  pages 23-27 of 07-13-19.pdf
+ds.s:     pages 30-38 of 07-13-19.pdf
+dsksav.s: page  40    of 07-13-19.pdf
+dskres.s: page  41    of 07-13-19.pdf
+dskio.s:  pages 42-43 of 07-13-19.pdf
+dsw.s:    page  45    of 07-13-19.pdf
+init.s    pages 47-51 of 07-13-19.pdf
+
 cas.s: pages 1-17 of 04-cas.pdf
-cat.c: pages 21-23 of 06-5-12.pdf
 
 ind.b:   page 2 of 08-rest.pdf
 lease.b: page 4 of 08-rest.pdf
diff --git a/scans/db.s b/scans/db.s
new file mode 100644
index 0000000..4ee59c4
--- /dev/null
+++ b/scans/db.s
@@ -0,0 +1,1217 @@
+" db
+
+   narg = ..+07777
+   lac i narg
+   sad d4
+   jmp start
+   lac narg
+   tad d5
+   dac rcorep
+   dac wcorep
+   lac i narg
+   sad d8
+   jmp start
+   sad d12
+   skp
+   jmp error
+   lac narg
+   tad d9
+   dac nlnamep
+   "
+start:
+   lac nlbufp
+   cma
+   tad o17777
+   cll
+   idiv
+   6
+   cll
+   lacq
+   mul
+   6
+   lacq
+   dac namesize
+   sys open; nlnamep: nlname; 0
+   dac symindex
+   sma
+   jmp 1f
+2:
+   dzm nlcnt
+   lac nlbufp
+   dac nlsize
+   jmp 3f
+1:
+   sys read; nlbuff; namesize;0
+   spa
+   jmp 2b
+   dac nlcnt
+   tad nlbufp
+   dac nlsize
+3:
+   lac symindex
+   sys close
+   sys open
+wcorep: corename; 1
+   dac wcore
+   sys open; rcorep: corename; 0
+   dac rcore
+   spa
+   jmp error
+   "
+   lac o52012
+   jms wchar
+   law dotdot
+   dac nsearch
+   jms nlsearch
+   jmp mloop
+   lac value
+   dac relocval
+   cma
+   tad d1
+   dac mrelocv
+   dzm sysflag
+mloop:
+   -1
+   dac nwords
+ml1:
+   jms rch
+   dac nchar1
+   sad o52
+   skp
+   jmp 1f
+   dzm nchar1
+   dac indflg
+1:
+   jms getexp
+   lac errf
+   sna
+   jmp cmd
+error:
+   dzm indflg
+   lac o40
+   dac rator
+   dzm errf
+   lac d1
+   sys write; errmes; 1
+   jmp mloop
+cmd:
+   lacq
+   sad o41
+   jmp patch
+   lac opfound
+   sna
+   jmp 1f
+   lac comflg
+   dzm comflg
+   sza
+   jmp 1f
+   lac curval
+   dac curdot
+   lac curreloc
+   dac dotrel
+1:
+   lacq
+   sad o42
+   jmp ascii
+   sad o12
+   jmp newln
+   sad o77
+   jmp symbol
+   sad o47
+   jmp saddress
+   sad o75
+   jmp address
+   sad o57
+   jmp octal
+   sad o72
+   jmp decimal
+   sad o136
+   skp
+   jmp 1f
+   dac sysflag
+   jmp mloop
+1:
+   sad o45
+   skp
+   jmp 1f
+   dzm sysflag
+   jmp mloop
+1:
+   sad d1
+   sys exit
+   sad o54
+   skp
+   jmp error
+   " comma
+   jms getexp
+   lac errf
+   sza
+   jmp error
+   law
+   dac comflg
+   lac curreloc
+   sza
+   jmp 1f
+   lac value
+   cma
+   dac nwords
+   jmp cmd
+1:
+   lac reldot
+   sna
+   jmp error
+   lac curval
+   cma
+   tad curdot
+   sma
+   jmp error
+   dac nwords
+   jmp cmd
+   "
+saddress:
+   lac curdot
+   dac 9f
+   dzm curdot
+   lac reldot
+   sza
+   lac relocval
+   tad 9f
+   jms prsym
+   lac o12
+   jms wchar
+   lac 9f
+   dac curdot
+   jmp mloop
+9:0
+   "
+symbol:
+   law prsym
+   dac type
+   jmp print
+   "
+octal:
+   law proct
+   dac type
+   jmp print
+   "
+ascii:
+   law prasc
+   dac type
+   jmp print
+   "
+decimal:
+   law prdec
+   dac type
+   jmp print
+   "
+address:
+   lac curdot
+   jms octw
+   5
+   lac curreloc
+   sza
+   jmp 1f
+   lac o12
+   jms wchar
+   jmp mloop
+1:
+   lac o162012
+   jms wchar
+   jmp mloop
+   "
+print:
+   lac sysflag
+   sza
+   jmp 2f
+   lac reldot
+   sza
+   jmp 1f
+   lac curdot
+   dac addr
+   jmp sprint
+2:
+   lac curdot
+   dac addr
+   jmp sprint
+1:
+   law inbuf
+   dac addr
+   lac curdot
+   dac 1f
+   lac rcore
+   sys seek; 1:0; 0
+   spa
+   jmp error
+   lac rcore
+   sys read; inbuf; 64
+   spa
+   jmp error
+   sna
+   jmp error
+   "
+sprint:
+   lac indflg
+   sna
+   jmp 2f
+   dzm indflg
+   lac i addr
+   and o17777
+   dac curdot
+   dzm reldot
+   tad mrelocv
+   spa
+   jmp print
+   dac curdot
+   lac d1
+   dac reldot
+   jmp print
+   "
+2:
+   lac o40
+   jms wchar
+   lac addr
+   dac 3f
+   lac i addr
+   jms i type
+   lac 3f
+   dac addr
+   isz addr
+   law prasc
+   sad type
+   jmp 2f
+   lac nl
+   jms wchar
+1:
+   isz nwords
+   jmp 1f
+   law prasc
+   sad type
+   skp
+   jmp mloop
+   lac nl
+   jms wchar
+   jmp mloop
+1:
+   isz curdot
+   nop
+   lac nwords
+   spa
+   jmp print
+   jmp 2b
+3:0
+   "
+prdec:     "temp
+proct:0
+   jms octw
+   6
+   jmp i proct
+   "
+patch:
+   lac opfound
+   sna
+   jmp error
+   lac curreloc
+   sna
+   jmp 1f
+   lac curval
+   tad relocval
+   skp
+1:
+   lac curval
+   dac inbuf
+   lac sysflag
+   sna
+   jmp 1f
+   lac inbuf
+   dac i curdot
+   jmp bump
+1:
+   lac reldot
+   sna
+   jmp error
+   lac curdot
+   dac 2f
+   lac wcore
+   spa
+   jmp error
+   sys seek; 2:0; 0
+   spa
+   jmp error
+   lac wcore
+   sys write; inbuf; 1
+   spa
+   jmp error
+bump:
+   -1
+   dac nwords
+   isz curdot
+   jmp print
+   "
+newln:
+   lac opfound
+   sna
+   jmp bump
+   jmp print
+   "
+getexp:0
+   dzm errf
+   lac o40
+   dac rator
+   dzm curval
+   dzm curreloc
+   dzm reloc
+   dzm value
+   dzm opfound
+xloop:
+   jms rch
+   lmq
+   sad o044
+   skp
+   jmp 1f
+   jms getspec
+   jms oprand
+   jmp xloop
+1:
+   tad om60
+   spa
+   jmp 1f
+   tad om10
+   sma
+   jmp 1f
+   lacq
+   jms getnum
+   jms oprand
+   jmp xloop
+1:
+   lacq
+   sad o56
+   jmp 1f
+   tad om141
+   spa
+   jmp 2f
+   tad om32
+   sma
+   jmp 2f
+1:
+   lacq
+   jms getsym
+   jms oprand
+   jmp xloop
+2:
+   lacq
+   tad om101
+   spa
+   jmp 1f
+   tad om32
+   spa
+   jmp 1b
+1:
+   lacq
+   sad o74
+   skp
+   jmp 1f
+   jms rch
+   alss 9
+   dac value
+   dzm reloc
+   jms oprand
+   jmp xloop
+1:
+   sad o40
+   jmp xloop
+   sad o55 "-
+   skp
+   jmp 1f
+2:
+   lac o40
+   sad rator
+   skp
+   jmp error
+   lacq
+   dac rator
+   jmp xloop
+1:
+   sad o53 "+
+   jmp 2b
+   lac curreloc
+   sna
+   jmp 1f
+   sad d1
+   skp
+   dac errf
+1:
+   lac o40
+   sad rator
+   jmp i getexp
+   dac errf
+   jmp i getexp
+   "
+getspec: 0
+      jms rch
+      sad o141
+      jmp spcac
+      sad o161 "q
+      jmp spcmq
+      sad o151 "i
+      jmp spcic
+      lmq
+      tad om60
+      spa
+      jmp 2f
+      tad om10
+      sma
+      jmp 2f
+      lacq
+      jms getnum
+      jmp spcai
+2:
+      law
+      dac errf
+      jmp getspec i
+spcac:
+      cla
+      jmp 1f
+spcmq:
+      lac d1
+      jmp 1f
+spcic:
+      lac d10
+      jmp 1f
+spcai:
+      lac value
+      tad dm6
+
+1:
+      tad o10000
+      dac value
+      lac d1
+      dac reloc
+      jmp i getspec
+   "
+getsym:0
+   lmq
+   law symbuf
+   dac symbufp
+   dzm symbuf
+   -8
+   dac symcnt
+   dzm nchar1
+   lac nopcom
+   dac skipt
+   skp
+storech:
+   imq
+   lac i symbufp
+   and o177000
+   sna
+   jmp 1f
+   omq
+   dac i symbufp
+   isz symbufp
+   dzm i symbufp
+   jmp 2f
+1:
+   llss 27
+   dac i symbufp
+   "
+2:
+   isz symcnt
+   skp
+   jmp endsym
+skipt:
+   nop " or jmp fill
+   jms rch
+   sad o76
+   skp
+   jmp 1f
+   lac symbuf
+   lrss 9
+   and o177
+   dac value
+   dzm reloc
+   jmp i getsym
+1:
+   sad o56
+   jmp storech
+   dac nchar1
+   tad om60
+   spa
+   jmp fill
+   tad m10
+   spa
+   jmp 2f
+   lac nchar1
+   tad om141
+   spa
+   jmp 1f
+   tad om32
+   spa
+   jmp 2f
+1:
+   lac nchar1
+   tad om101
+   spa
+   jmp fill
+   tad om32
+   sma
+   jmp fill
+2:
+   lac nchar1
+   dzm nchar1
+   jmp storech
+   "
+fill:
+   lac trafill
+   dac skipt
+   lac o40
+   jmp storech
+   "
+endsym:
+   lac symbuf
+   sad o56040
+   jmp dotsym
+   law symbuf
+   dac nsearch
+   jms nlsearch
+   jmp undef
+   dzm nsearch
+   jmp i getsym
+   "
+dotsym:
+   lac curdot
+   dac value
+   lac dotrel
+   dac reloc
+   jmp i getsym
+   "
+undef:
+   dzm nsearch
+   law
+   dac errf
+   jmp i getsym
+   "
+getnum:0
+   dzm reloc
+   dzm value
+num1:
+   tad om60
+   imq
+   lac value
+   alss 3
+   omq
+   dac value
+   jms rch
+   dac nchar1
+   sad o162
+   jmp nrel
+   tad om60
+   spa
+   jmp i getnum
+   tad om10
+   sma
+   jmp i getnum
+   lac nchar1
+   dzm nchar1
+   jmp num1
+nrel:
+   dzm nchar1
+   lac d1
+   dac reloc
+   jmp i getnum
+   "
+oprand:0
+   lac rator
+   sad o53
+   jmp opplus
+   sad o40
+   jmp opor
+   sad o55
+   jmp opminus
+opplus:
+   lac value
+   tad curval
+   dac curval
+1:
+   lac curreloc
+   tad reloc
+   dac curreloc
+   jmp retop
+   "
+opor:
+   lac value
+   lmq
+   lac curval
+   omq
+   dac curval
+   jmp 1b
+   "
+opminus:
+   lac curval
+   cma
+   tad value
+   cma
+   dac curval
+   lac reloc
+   cma
+   tad d1
+   tad curreloc
+   dac curreloc
+retop:
+   lac o40
+   dac rator
+   dac opfound
+   jmp i oprand
+   "
+prasc:0
+   jms wchar
+   jmp i prasc
+   "
+prsym:0
+   dac word
+   dzm relflg
+   dzm relocflg
+   dzm nsearch
+   and o760000
+   sad o760000
+   jmp plaw
+   sad o20000
+   jmp pcal
+   and o740000
+   sad o640000
+   jmp peae
+   sad o740000
+   jmp popr
+   sad o700000
+   jmp piot
+   sna
+   jmp poct
+   jms nlsearch
+   jmp poct
+   jms wrname
+   lac o40
+   jms wchar
+   lac word
+   and o20000
+   sna
+   jmp 1f
+   lac o151040
+   jms wchar
+   lac word
+   xor o20000
+   dac word
+1:
+symadr:
+   lac d1
+   dac relflg
+   dac relocflg
+   lac word
+   and o17777
+   tad mrelocv
+   sma
+   jmp 1f
+   tad relocval
+   dzm relocflg
+1:
+pradr:
+   dac addr
+   jms nlsearch
+   jmp octals
+pr1:
+   dzm relflg
+   jms wrname
+   lac value
+   sad addr
+   jmp i prsym
+   cma
+   tad d1
+   tad addr
+   sma
+   jmp 1f
+   cma
+   tad d1
+   dac addr
+   lac o55
+   jms wchar
+   jmp 2f
+1:
+   dac addr
+   lac o53
+   jms wchar
+2:
+   lac addr
+   jms octw
+   1
+   jmp i prsym
+   "
+plaw:
+   lac d1
+   dac relocflg
+   lac word
+   and o17777
+   tad mrelocv
+   sma
+   jmp 1f
+   tad relocval
+   dzm relocflg
+1:
+   dac addr
+   law
+   dac relflg
+   lac addr
+   lms nlsearch
+   jmp poct
+   dac symindex
+   law laws
+   jms wrname
+   lac o40
+   jms wchar
+3:
+   lac symindex
+   jmp pr1
+2:0
+9:0
+   "
+peae:
+   lac word
+   jms nlsearch
+   jmp 1f
+   jms wrname
+   jmp i prsym
+1:
+   lac word
+   and o777700
+   jms nlsearch
+   jmp 1f
+   jms wrname
+   lac o40
+   jms wchar
+   lac word
+   and o77
+   jms octw
+   1
+   jmp i prsym
+1:
+   law eaes
+   dac addr
+   jmp nfnd
+   "
+popr:
+   law oprs
+   jmp 1f
+piot:
+   law iots
+1:
+   dac addr
+   lac word
+   jms nlsearch
+   jmp 1f
+   jms wrname
+   jmp i prsym
+1:
+nfnd:
+   lac addr
+   jms wrname
+octala:
+   dzm relflg
+   lac o40
+   jms wchar
+   lac word
+   and o37777
+   lmq
+   lac relocflg
+   sna
+   jmp 1f
+   lacq
+   tad mrelocv
+   imq
+1:
+   lacq
+   jms octw
+   1
+   lac relocflg
+   sna
+   jmp i prsym
+   lac o162
+   jms wchar
+   dzm relocflg
+   jmp i prsym
+   "
+poct:
+   lac word
+   jms octw
+   6
+   jmp i prsym
+   "
+pcal:
+   lac word
+   sna
+   jmp poct
+   and o17777
+   jms nlsearch
+   jmp 1f
+   dac addr
+   law syss
+   jms wrname
+   lac o40
+   jms wchar
+   lac addr
+   jms wrname
+   jmp i prsym
+   "
+1:
+   lac word
+   and o20000
+   sza
+   jmp poct
+   jmp symadr
+   "
+wrname:0
+   tad dm1
+   dac 10
+   -4
+   dac 3f
+1:
+   lac i 10
+   dac 2f
+   imq
+   cla
+   llss 9
+   sad o40
+   jmp i wrname
+   jms wchar
+   lac 2f
+   and o177
+   sad o40
+   jmp i wrname
+   jms wchar
+   isz 3f
+   jmp 1b
+   jmp i wrname
+2:0
+3:0
+   "
+nlsearch:0
+   dac match
+   lac brack
+   dac best
+   dzm minp
+1:
+   lac nlbufp
+   tad dm6
+   dac cnlp
+nloop:
+   lac cnlp
+   tad d6
+   dac cnlp
+   lmq
+   cma
+   tad nlsize
+   spa
+   jmp nlend
+   lac nsearch
+   sza
+   jmp testn
+   lacq
+   tad d3
+   dac np
+   lac i np
+   sna
+   jmp nloop
+   isz np
+   lac i np
+   dac treloc
+   sad relocflg
+   skp
+   jmp nloop
+   isz np
+   iac i np
+   dac tvalue
+   sad match
+   jmp nlok
+   lac relocflg
+   sna
+   jmp nloop
+   lac relflg
+   sna
+   jmp nloop
+   -1
+   tad tvalue
+   cma
+   tad match
+   spa
+   jmp nloop
+   dac 2f
+   tad mbrack
+   sma
+   jmp nloop
+   lac best
+   cma
+   tad d1
+   tad 2f
+   sma
+   jmp nloop
+   lac 2f
+   dac best
+   lac tvalue
+   dac value
+   lac treloc
+   dac reloc
+   lac cnlp
+   dac minp
+   jmp nloop
+   "
+2:0
+   "
+testn:
+   lacq
+   dac minp
+   -4
+   dac value
+   lac match
+   dac inbuf
+1:
+   lac i minp
+   sad i inbuf
+   skp
+   jmp nloop
+   isz minp
+   isz inbuf
+   isz value
+   jmp 1b
+   lac i minp
+   dac treloc
+   isz minp
+   lac i minp
+   dac tvalue
+   jmp nlok
+   "
+nlend:
+   lac relflg
+   sna
+   jmp i nlsearch
+   lac dotrel
+   sad relocflg
+   skp
+   jmp 1f
+   -1
+   tad curdot
+   cma
+   tad match
+   spa
+   jmp 2f
+   cma
+   tad d1
+2:
+   tad brack
+   spa
+   jmp 1f
+   tad mbrack
+   tad best
+   spa
+   jmp 1f
+   lac curdot
+   dac value
+   lac dotrel
+   dac reloc
+   law o56040
+   dac minp
+1:
+   lac minp
+   sza
+   isz nlsearch
+   jmp i nlsearch
+nlok:
+   lac tvalue
+   dac value
+   lac treloc
+   dac reloc
+   lac cnip
+   isz nlsearch
+   jmp i nlsearch
+   "
+nlerr:
+   law
+   dac errf
+   jmp i nlsearch
+   "
+rch:0
+   lac nchar1
+   dzm nchar1
+   sza
+   jmp i rch
+1:
+   lac nchar
+   dzm nchar
+   sza
+   jmp i rch
+   cla
+   sys read; char; 1
+   lac char
+   and o177
+   dac nchar
+   lac char
+   lrss 9
+   sna
+   jmp 1b
+   jmp i rch
+   "
+wchar:0
+   dac char
+   lac d1
+   sys write; char; 1
+   jmp i wchar
+   "
+octw: 0
+   isz octw
+   imq
+   cla cll
+   llss 3
+   alss 6
+   llss3
+   tad o60060
+   dac obuf
+   cla
+   llss 3
+   alss 6
+   llss 3
+   tad o60060
+   dac obuf+1
+   cla
+   llss 3
+   alss 6
+   llss 3
+   tad o60060
+   dac obuf+2
+   lac d1
+   sys write; obuf; 3
+   jmp i octw
+m10: -10
+   "
+   "
+o54:054
+d6:6
+o52012:052012
+d5:5
+d9:9
+d12:12
+d8:8
+d3:3
+o177:0177
+o136: 0136
+o45: 045
+sysflag: 0
+char:0
+d2:2
+o162012:0162012
+mrelocv:-010000
+relocval:010000
+nwords:0
+errf:0
+rator:0
+d1:1
+errmes:077012
+o12:012
+curval:0
+curreloc:0
+curdot:0
+reldot:
+dotrel:0
+value:0
+reloc:0
+o77:077
+o57:057
+o72:072
+o50:050
+type:proct
+o162:0162
+nl:012
+om100:-0100
+d2:2
+symbuf: .=.+5
+inbuf:.=.+64
+o100:0100
+opfound:0
+wcore:0
+symindex:0
+rcore:0
+o56:056
+om60:-060
+om10:-010
+o56:056
+om141:-0141
+o141: 0141
+oO44: 044
+o151: 0151
+o161: 0161
+om101: -0101
+om32:-032
+o40:040
+o55:055
+o53:053
+symbufp:0
+symcnt:0
+nopcom:nop
+dm6: -6
+d10: 10
+trafill: jmp fill
+nchar1:0
+nchar:0
+o177000:0177000
+o56040:056040
+nsearch:0
+word:0
+relflg:0
+relocflg:0
+o740000:0740000
+o640000:0640000
+o700000:0700000
+o17777:017777
+o20000:020000
+o10000: 010000
+o151040:0151040
+eaes:0145141;0145040
+laws: 0154141;0167040
+oprs:0157160;0162040
+iots:0151157;0164040
+syss:0163171;0163040
+corename:0143157;0162145;040040;040040
+nlname:0156056;0157165;0164040;040040
+dotdot: <..>; 040040; 040040; 040040
+addr:0
+o37777:037777
+dm1:-1
+match:0
+rwdflg:0
+nlbufp:nlbuff
+nlsize:0
+dm6:-6
+cnlp:0
+o377777:0377777
+minp:0
+d4:4
+np:0
+nlcnt:0
+obuf:.=.+3
+o60060:060060
+o75:075
+best: 0
+o60000:060000
+comflg:0
+nlbufp:nlbuff
+brack: 30
+mbrack: -30
+o777700:0777700
+o41:041
+o42:042
+o760000:0760000
+o40000:040000
+tvalue: 0
+treloc: 0
+o151:0151
+o47: 047
+o52:052
+indflg: 0
+o74:074
+o76:076
+nlbufp: nlbuff
+   nlbuff = .
\ No newline at end of file
diff --git a/scans/dmabs.s b/scans/dmabs.s
new file mode 100644
index 0000000..fce7825
--- /dev/null
+++ b/scans/dmabs.s
@@ -0,0 +1,256 @@
+   " dmabs
+
+   lac o17
+   sys creat; punout
+   spa
+   sys save
+   dac fo
+   lac 017777
+   tad d1
+   dac name
+   jms space
+   100
+
+loop:
+   dzm oldsum
+   lac initcmd
+   dac comand
+   lac i 017777
+   sad d4
+   jmp stop
+   tad dm4
+   dac i 017777
+   lac name
+   tad d4
+   dac name
+
+dump1:
+   lac comand
+   xor dactra
+   dac tracmd
+
+dump2:
+   sys open; name: 0; 0
+   spa
+   jmp opnerr
+   dac fi
+   -bootsiz
+   dac c1
+   law boot-1
+   dac 8
+1:
+   lac i 8
+   jms put
+   isz c1
+   jmp 1b
+   lac bootcmd
+   lrs 12
+   jms put1
+   lac bootcmd
+   lrs 6
+   jms put1
+   lac bootcmd
+   and o77
+   xor o300
+   jms put2
+
+   jms space
+   3
+
+dump3:
+   -1
+   tad bufp
+   dac 8
+   -64
+   dac c1
+1:
+   dzm i 8
+   isz c1
+   jmp 1b
+   lac fi
+   sys read; bufp: buf; 64
+   sna
+   jmp done
+   dac count
+   -1
+   tad bufp
+   dac 8
+   -64
+   dac c1
+   cla
+1:
+   add i 8
+   isz c1
+   jmp 1b
+   sna
+   jmp dump4
+   dac newsum
+   lac comand
+   jms put
+   lac count
+   jms put
+   lac oldsum
+   add comand
+   add count
+   jms put
+   lac newsum
+   dac oldsum
+   jms space
+   3
+   -1
+   tad bufp
+   dac 8
+   -1
+   tad count
+   cma
+   dac c1
+1:
+   lac i 8
+   jms put
+   isz c1
+   jmp 1b
+   jms space
+   10
+
+dump4:
+   lac comand
+   tad count
+   dac comand
+   jmp dump3
+
+done:
+   lac tracmd
+   jms put
+   cla
+   jms put
+   lac oldsum
+   add tracmd
+   jms put
+   jms space
+   20
+   lac fi
+   sys close
+   jmp loop
+
+stop:
+   cla
+   jms put
+   jms space
+   100
+   sys exit
+
+space: 0
+   -1
+   tad i space
+   cma
+   dac c1
+   isz space
+1:
+   lac o400
+   jms put2
+   isz c1
+   jmp 1b
+   jmp i space
+
+put: 0
+   dac 1f
+   lrs 12
+   jms put1
+   lac 1f
+   lrs 6
+   jms put1
+   lac 1f
+   jms put1
+   jmp i put
+1:0
+
+put1:0
+   and o77
+   xor o200
+   jms put2
+   jmp i put1
+
+put2: 0
+   dac 1f
+   lac fo
+   sys write; 1f; 1
+   jmp i put2
+1: 0
+
+boot:
+   org = 017740
+2:
+   jms get1-boot+org
+   dac cmd-boot+org
+   jms get1-boot+org
+   cma
+   dac cnt-boot+org
+   jms get2-boot+org
+   xor sum-boot+org
+   dzm sum-boot+org
+   cla cll sza
+   hlt
+   isz cnt-boot+org
+1:
+   jms get1-boot+org
+cmd: 0
+   isz cmd-boot+org
+   isz cnt-boot+org
+   jmp 1b-boot+org
+   jmp 2b-boot+org
+get1: 0
+   jms get2-boot+org
+   dac get2-boot+org
+   add sum-boot+org
+   dac sum-boot+org
+   lac get2-boot+org
+   jmp i get1-boot+org
+get2: 0
+   iot 0144
+1:
+   iot 0101
+   jmp 1b-boot+org
+   iot 0112
+   jmp i get2-boot+org
+sum: 0
+   cnt = sum+1
+   bootsiz = .-boot
+bootcmd: jmp org
+
+opnerr:
+   lac name
+   dac 1f
+   lac d1
+   sys write; 1: 0; 4
+   lac d1
+   sys write; mes; 2
+   jmp loop
+mes:
+   040;077012
+
+comand: 0
+tracmd: 0
+   d1: 1
+.17777: 017777
+o77: 077
+o200: 0200
+o300: 0300
+d4: 4
+d64: 64
+dm4: -4
+o400: 0400
+punout: <pp>;<to>;<ut>;040040
+o17: 017
+
+fi: 0
+fo: 0
+count: 0
+oldsum: 0
+newsum: 0
+daccmd: dac
+dactra: dac jmp
+initcmd: dac 0
+c1: 0
+buf:
+
+iot = 0700000
\ No newline at end of file
diff --git a/scans/ds.s b/scans/ds.s
new file mode 100644
index 0000000..2aa0f93
--- /dev/null
+++ b/scans/ds.s
@@ -0,0 +1,501 @@
+" ds
+
+   lac 017777 i
+   sad d8
+   skp
+   sys exit
+   lac 017777
+   tad d5
+   dac .+3
+   law 017
+   sys creat; ..
+   dac fo
+   law 017
+   sys creat; scrname
+   spa; jms error
+   dac fso
+   sys open; scrname; 0
+   spa; jms error
+   dac fsi
+   sys chdir; dd
+   spa; jms error
+   lac d1
+   sys write; pass1; 1
+   law fsobuf
+   dac fsopt
+   dzm nfiles
+   law fbuf
+   dac filp
+   dzm ndirs
+   law dbuf
+   dac dirp
+   dzm fsloc
+   sys open; dotdot; 0
+   spa; jms error
+   dac fd
+   jms readdir; dotdot
+   law statbuf
+   sys status; dotdot; dotdot
+   spa; jms error
+   lac statbuf+12 " i index
+   dac dirp i
+   isz dirp
+   -1
+   tad nfiles
+   cma
+   dac ddfiles
+   law fbuf
+   dac ddfilp
+
+loop:
+   -1
+   tad ndirs
+   cma
+   dac c1
+   law dbuf
+   dac i1
+
+1:
+   isz i1
+   lac i1 i
+   sad ddfilp i
+   jmp 2f
+   isz i1
+   isz c1
+   jmp 1b
+
+   lac ddfilp
+   tad i1
+   dac i1
+   lac i1 i
+   dac .+3
+   lac fsi
+   sys seek; ..; 0
+   lac fsi
+   sys read; scrname; 4
+   law statbuf
+   sys status; dotdot; scrname
+   spa; jms error
+   lac statbuf+0 " flags
+   and o20
+   sna
+   jmp 2f
+   sys open; scrname; 0
+   spa; jms error
+   dac fd
+   jms readdir; scrname
+   lac ddfilp i
+   dac dirp i
+   isz dirp
+
+2:
+   isz ddfilp
+   isz ddfilp
+   isz ddfiles
+   jmp loop
+
+" output phase
+
+   lac fso
+   sys write; fsobuf; 64
+   lac d1
+   sys write; pass2; 2
+   -500
+   dac c1
+
+1:
+   law dbuf+2
+   dac i1
+   dzm fflg
+   law fbuf
+   dac i2
+   r1
+   tad nfiles
+   cma
+   dac c2
+
+2:
+   lac c1
+   tad d501
+   sad i2 i
+   skp
+   jmp 3f
+   -1
+   tad i1
+   dac i3
+   iac i3 i
+   dac c3
+   law fbuf
+   dac i3
+0:
+   lac i3 i
+   sad c3
+   jmp 0f
+   isz i3
+   isz i3
+   jmp 0b
+0:
+   lac i3
+   tad d1
+   dac c3
+   lac c3 i
+   dac .+3
+   lac fsi
+   sys seek; ..; 0
+   lac fsi
+   sys read; scrname; 4
+   lac i2
+   tad d1
+   dac c3
+   lac c3 i
+   dac .+3
+   lac fsi
+   sys seek; ..; 0
+   lac fsi
+   sys read; dd; 4
+   lac fflg
+   sza
+   jmp 0f
+
+   lac nlinkt
+   sad nlinka
+   skp
+   jms fishy
+   dzm nlinka
+   law 012
+   jms putc
+   law statbuf
+   sys status; scrname; dd
+   spa; jms error
+   -1
+   tad statbuf+9
+   cma
+   dac nlinkt
+   -1
+   dac fflg
+   jms longout
+   law 012
+   jms putc
+0:
+   isz nlinka
+   jms putname; scrname
+   jms putname; dd
+   law 012
+   jms putc
+
+3:
+   isz i2
+   isz i2
+   lac i2
+   sad i1 i
+   skp
+   jmp .+3
+   isz i1
+   isz i1
+   isz c2
+   jmp 2b
+
+   isz c1
+   jmp 1b
+   lac nlinkt
+   sad nlinka
+   skp
+   jms fishy
+
+   sys chdir; system
+   jmp done
+
+fishy: 0
+   jms asters
+   jms asters
+   law 012
+   jms putc
+   lac d1
+   sys write; 1f; 1
+   jmp fishy i
+1: 052012
+
+nlinka: 0
+nlinkt: 0
+
+asters: 0
+   -10
+   dac c
+1:
+   law 052
+   jms putc
+   isz c
+   jmp 1b
+   jmp asters i
+
+longout: 0
+   lac statbuf+12 " i
+   jms octal; -3
+   lac statbuf+0 " flags
+   jms octal; -2
+   lac statbuf+8 " uid
+   jms octal; -2
+   -1
+   tad statbuf+9 " nlinks
+   cma
+   jms octal; -2
+   lac statbuf+10
+   jms octal; -5
+   jmp longout i
+
+readdir: 0
+   law 012
+   jms putc
+   law 012
+   jms putc
+   jms asters
+   lac readdir i
+   dac 5f
+   dac .+2
+   jms putname; ..
+   jms asters
+   law 012
+   jms putc
+   law 012
+   jms putc
+   isz readdir
+   isz ndirs
+   lac filp
+   dac dirp i
+   isz dirp
+0:
+   jms copyz; buf; 64
+   lac fd
+   sys read; buf; 64
+   spa; jms error
+   sna
+   jmp 4f
+   -8
+   dac c1
+   law buf
+   dac i1
+1:
+   lac i1 i
+   sna
+   jmp 3f
+
+   isz nfiles
+   dac filp i
+   isz filp
+   lac fsloc
+   dac filp i
+   tad d4
+   dac fsloc
+   isz filp
+   lac i1
+   tad d1
+   dac .+4
+   law statbuf
+   sys status; 5:..; ..
+   spa; jms error
+   jms longout
+   lac i1
+   tad d1
+   dac .+2
+   jms putname; ..
+   law 012
+   jms putc
+   lac i1
+   dac 8
+   lac 8 i
+   dac fsopt i
+   isz fsopt
+   lac 8 i
+   dac fsopt i
+   isz fsopt
+   lac 8 i
+   dac fsopt i
+   isz fsopt
+   lac 8 i
+   dac fsopt i
+   isz fsopt
+   law fsobuf+64
+   sad fsopt
+   skp
+   jmp 3f
+   lac fso
+   sys write; fsobuf; 64
+   law fsobuf
+   dac fsopt
+
+3:
+   law 8
+   tad i1
+   dac i1
+   isz c1
+   jmp 1b
+   jmp 0b
+4:
+   lac fd
+   sys close
+   jmp readdir i
+
+putname: 0
+   -1
+   tad putname i
+   dac 8
+   -4
+   dac c
+1:
+   lac 8 i
+   lrss 9
+   jms putc
+   llss 9
+   jms putc
+   isz c
+   jmp 1b
+   isz putname
+   jmp putname i
+
+octal: 0
+   lmq
+   lac d5
+   tad octal i
+   cma
+   dac c
+1:
+   llss 3
+   isz c
+   jmp 1b
+   lac octal i
+   dac c
+1:
+   ecla llss 3
+   tad o60
+   jms putc
+   isz c
+   jmp 1b
+   law 040
+   jms putc
+   isz octal
+   jmp octal i
+
+error: 0
+   -1
+   tad error
+   hlt
+   sys save
+
+copyz: 0
+   -1
+   tad copyz i
+   dac 8
+   isz copyz
+   -1
+   tad copyz i
+   cma
+   dac 2f
+   isz copyz
+1:
+   dzm 8 i
+   isz 2f
+   jmp 1b
+   jmp copyz i
+2: 0
+
+done:
+   lac noc
+   sna
+   sys exit
+   and d1
+   sna cla
+   jmp 1f
+   jms putc
+   jmp done
+1:
+   lac noc
+   rcr
+   dac 1f
+   lac fo
+   sys write; obuf; 1;..
+   sys exit
+
+putc: 0
+   and o177
+   dac 2f+1
+   lac opt
+   dac 2f
+   add o400000
+   dac opt
+   spa
+   jmp 1f
+   lac 2f i
+   xor 2f+1
+   jmp 3f
+1:
+   lac 2f+1
+   alss 9
+3:
+   dac 2f i
+   isz noc
+   lac noc
+   sad d128
+   skp
+   jmp putc i
+   lac fo
+   sys write; obuf; 64
+   lac iopt
+   dac opt
+   dzm noc
+   jmp putc i
+2: 0;0
+opt: obuf
+iopt: obuf
+noc: 0
+fo: 1
+
+d1: 1
+o177: 0177
+o400000: 0400000
+d128: 128
+d4: 4
+d5: 5
+d8: 8
+o60: 060
+o20: 020
+d501: 501
+
+dd:
+   <dd>; 040040; 040040; 040040
+dotdot:
+   056056; 040040; 040040; 040040
+system:
+   <sy>;<st>;<em>; 040040
+scrname:
+   <*s>;<rc>;040040;040040
+pass2:
+   <i
+pass1:
+   <i 012
+
+fso: .=.+1
+fsi: .=.+1
+fsloc: .=.+1
+nfiles: .=.+1
+fflg: .=.+1
+buf: .=.+64
+obuf: .=.+64
+fd: .=.+1
+filp: .=.+1
+ddfilp: .=.+1
+ddfiles: .=.+1
+statbuf: .=.+13
+c: .=.+1
+i1: .=.+1
+i2: .=.+1
+i3: .=.+1
+c1: .=.+1
+c2: .=.+1
+c3: .=.+1
+ndirs: .=.+1
+dirp: .=.+1
+fsopt: .=.+1
+fsobuf: .=.+64
+dbuf: .=.+100
+fbuf:
+   
\ No newline at end of file
diff --git a/scans/dskio.s b/scans/dskio.s
new file mode 100644
index 0000000..30cf100
--- /dev/null
+++ b/scans/dskio.s
@@ -0,0 +1,78 @@
+" dskio
+
+dskrd0: 0
+   dzm side
+   jms dskio; 02000
+   jmp i dskrd0
+
+dskwr0: 0
+   dzm side
+   jms dskio; 03000
+   jmp i dskwr0
+
+dskrd1: 0
+   lmq
+   lac o200000
+   dac side
+   lacq
+   jms dskio; 02000
+   jmp i dskrd1
+
+dskwr1: 0
+   lmq
+   lac o200000
+   dac side
+   lacq
+   jms dskio; 03000
+   jmp i dskwr1
+
+
+iskio: 0
+   cll; idiv; 80
+   dac 2f
+   lacq
+   idiv; 10
+   dac 3f
+   lls 22
+   xor 3f
+   als 8
+   dac 3f
+   lac 2f
+   idiv; 10
+   dac 2f
+   lls 22
+   xor 2f
+   xor 3f
+   xor side
+   dac 2f
+   -10
+   dac 3f
+1:
+   dscs
+   -640
+   dslw
+   lac dskbufp
+   dslm
+   lac 2f
+   dsld
+   lac dskio i
+   dsls
+   dssf
+   jmp .-1
+   dsrs
+   sma
+   jmp 1f
+   isz 3f
+   jmp 1b
+   hlt
+1:
+   isz dskio
+   jmp i dskio
+2: 0
+3: 0
+
+o200000: 0200000
+dskbufp: dskbuf
+
+side: .=.+1
+dskbuf: .=.+640
\ No newline at end of file
diff --git a/scans/dskres.s b/scans/dskres.s
new file mode 100644
index 0000000..ac432bb
--- /dev/null
+++ b/scans/dskres.s
@@ -0,0 +1,26 @@
+" dskres
+
+   iof
+   hlt
+   dzm track
+   -640
+   dac c1
+1:
+   lac track
+   jms dskrd0
+
+   lac track
+   jms dskwr1
+
+   lac track
+   tad d10
+   dac track
+   isz c1
+   jmp 1b
+
+   hlt
+   sys exit
+
+track: 0
+c1: 0
+d10: 10
\ No newline at end of file
diff --git a/scans/dsksav.s b/scans/dsksav.s
new file mode 100644
index 0000000..2e79929
--- /dev/null
+++ b/scans/dsksav.s
@@ -0,0 +1,26 @@
+" dsksav
+
+   iof
+   hlt
+   dzm track
+   -640
+   dac c1
+1:
+   lac track
+   jms dskrd1
+
+   lac track
+   jms dskwr0
+
+   lac track
+   tad d10
+   dac track
+   isz c1
+   jmp 1b
+
+   hlt
+   sys exit
+
+track: 0
+c1: 0
+d10: 10
diff --git a/scans/dsw.s b/scans/dsw.s
new file mode 100644
index 0000000..03f8ff2
--- /dev/null
+++ b/scans/dsw.s
@@ -0,0 +1,37 @@
+" dsw
+
+   lac djmp
+   dac .-1
+   oas cla
+   oma
+   tad d1
+   dac t1
+   sys open; dd; 0
+1:
+   lac d2
+   sys read; dir; 8
+   sna
+   sys exit
+   lac dir
+   sna
+   jmp 1b
+   isz t1
+   jmp 1b
+
+wr:
+   lac d1
+   sys write; dir+1; 4
+   lac d1
+   sys write; o12; 1
+   sys save
+io:
+   sys unlink; dir+1
+   sys exit
+
+d1: 1
+d2: 2
+o12: 012
+t1: 0
+djmp: jmp do
+dd: 056056;040040;040040;040040
+dir: .=.+8
\ No newline at end of file
diff --git a/scans/init.s b/scans/init.s
new file mode 100644
index 0000000..69284d4
--- /dev/null
+++ b/scans/init.s
@@ -0,0 +1,291 @@
+" init
+
+   -1
+   sys intrp
+   jms init1
+   jms init2
+1:
+   sys rmes
+   sad pid1
+   jmp 1f
+   sad pid2
+   jms init2
+   jmp 1
+1:
+   jms init1
+   jmp 1
+
+init1: 0
+   sys fork
+   jmp 1f
+   sys open; ttyin; 0
+   sys open; ttyout; 1
+   jmp login
+1:
+   dac pid1
+   jmp init1 i
+
+init2: 0
+   sys fork
+   jmp 1f
+   sys open; keybd; 0
+   sys open; displ; 1
+   jmp login
+1:
+   dac pid2
+   jmp init2 i
+
+login:
+   -1
+   sys intrp
+   sys open; password; 0
+   lac d1
+   sys write; m1; m1s
+   jms rline
+   lac ebufp
+   dac tal
+1:
+   jms gline
+   law ibuf-1
+   dac 8
+   law obuf-1
+   dac 9
+2:
+   lac 8 i
+   sac o12
+   lac o72
+   sad 9 i
+   skp
+   jmp 1b
+   sad o72
+   skp
+   jmp 2b
+   lac 9 i
+   sad o72
+   jmp 1f
+   -1
+   tad 9
+   dac 9
+   lac d1
+   sys write; m3; m3s
+   jms rline
+   law ibuf-1
+   dac 8
+2:
+   lac 8 i
+   sad o12
+   lac o72
+   sad 9 i
+   skp
+   jmp error
+   sad o72
+   skp
+   jmp 2b
+1:
+   dzm nchar
+   law dir-1
+   dac 8
+1:
+   lac 9 i
+   sad o72
+   jmp 1f
+   dac char
+   lac nchar
+   sza
+   jmp 2f
+   lac char
+   alss 9
+   xor o40
+   dac 8 i
+   dac nchar
+   jmp 1b
+2:
+   lac 8
+   dac nchar
+   lac nchar i
+   and o777000
+   xor char
+   dac nchar i
+   dzm nchar
+   jmp 1b
+1:
+   dzm nchar
+1:
+   lac 9 i
+   sad o12
+   jmp 2f
+   tad om60
+   lmq
+   lac nchar
+   cll; als 3
+   omq
+   dac nchar
+   jmp 1b
+2:
+   lac nchar
+   sys setuid
+   sys chdir; dd
+   sys chdir; dir
+
+   lac d2
+   sys close
+   sys open; sh; 0
+   sma
+   jmp 1f
+   sys link; system; sh; sh
+   spa
+   jmp error
+   sys open; sh; 0
+   spa
+   jmp error
+   sys unlink; sh
+1:
+   law 017700
+   dac 9
+   law boot-1
+   dac 8
+1:
+   lac 8 i
+   dac 9 i
+   sza
+   jmp 1b
+   jmp 017701
+
+boot:
+   lac d2
+   lmq
+   sys read; 4096; 07700
+   lacq
+   sys close
+   jmp 4096
+   0
+
+rline: 0
+   law ibuf-1
+   dac 8
+1:
+   cla
+   sys read; char; 1
+   lac char
+   lrss 9
+   sad o100
+   jmp rline+1
+   sad o43
+   jmp 2f
+   dac 8 i
+   sad o12
+   jmp rline i
+   jmp 1b
+2:
+   law ibuf-1
+   sad 8
+   jmp 1b
+   -1
+   tad 8
+   dac 8
+   jmp 1b
+
+gline: 0
+   law obuf-1
+   dac 8
+1:
+   jms gchar
+   dac 8 i
+   sad o12
+   jmp gline i
+   jmp 1b
+
+gchar: 0
+   lac tal
+   sad ebufp
+   jmp 1f
+   ral
+   lac tal i
+   snl
+   lrss 9
+   and o777
+   lmq
+   lac tal
+   add o400000
+   dac tal
+   lacq
+   sna
+   jmp gchar+1
+   jmp gchar i
+1:
+   lac bufp
+   dac tal
+1:
+   dzm tal i
+   isz tal
+   lac tal
+   sad ebufp
+   skp
+   jmp 1b
+   lac bufp
+   dac tal
+   lac d2
+   sys tead; buf; 64
+   sna
+   jmp error
+   jmp gchar+1
+
+error:
+   lac d1
+   sys write; m2; m2s
+   lac d1
+   sys smes
+   sys exit
+
+m1:
+   012; <lo>;<gi>;<n;<:;<
+m1s = .-m1
+m2:
+   <?; 012
+m2s = .-m2
+m3:
+   <pa>;<ss>;<wo>;<rd>;<: 040
+m3s = .-m3
+dd:
+   <dd>;040040;040040;040040
+dir:
+   040040;040040;040040;040040
+
+ttyin:
+   <tt>;<yi>;<n 040;040040
+ttyout:
+   <tt>;<yo>;<ut>; 040040
+keybd:
+   <ke>;<yb>;<oa>;<rd>
+displ:
+   <di>;<sp>;<la>;<y 040
+sh: 
+   <sh>; 040040;040040;040040
+system:
+   <sy>;<st>;<em>; 040040
+password:
+   <pa>;<ss>;<wo>;<rd>
+
+d1: 1
+o43: 043
+o100: 0100
+o400000; 0400000
+d2: 2
+o12: 012
+om60: -060
+d3: 3
+ebufp: buf+64
+bufp: buf
+o777: 0777
+o777000: 0777000
+o40: 040
+o72: 072
+
+ibuf: .=.+100
+obuf: .=.+100
+tal: .=.+1
+buf: .=.+64
+char: .=.+1
+nchar: .=.+1
+pid1: .=.+1
+pid2: .=.+1
diff --git a/src/cmd/cat.s b/src/cmd/cat.s
index 39b6a87..9a5e65e 100644
--- a/src/cmd/cat.s
+++ b/src/cmd/cat.s
@@ -58,7 +58,7 @@ nofiles:
 
 done:
    lac noc
-   sns
+   sna
      sys exit
    and d1
    sna cla
diff --git a/tools/a7out b/tools/a7out
index 2733355..591b242 100755
--- a/tools/a7out
+++ b/tools/a7out
@@ -51,12 +51,12 @@ sub load_code {
         $Mem[$i] = 0;
     }
 
-    # Set up two file open filehandles
+    # Set up some open filehandles
     $FD[0] = \*STDIN;
     $FD[1] = \*STDOUT;
     $FD[8] = \*STDERR;		# According to cat.s (uses d8 == 8)
 
-    # Open up the file
+    # Open up the PDP-7 executable file
     open( my $IN, "<", $filename ) || die("Unable to open $filename: $!\n");
     while (<$IN>) {
         chomp;
@@ -122,7 +122,7 @@ sub set_arguments {
         for (my $i=0; $i < length($str); $i += 2) {
           my $c1= substr($str, $i, 1) || "";
           my $c2= substr($str, $i+1, 1) || "";
-          #printf("Saving %06o to %05o\n", (ord($c1) << 9 ) | ord($c2), $addr);
+          #printf("Saving %06o to %06o\n", (ord($c1) << 9 ) | ord($c2), $addr);
           $Mem[$addr++]= (ord($c1) << 9 ) | ord($c2);
         }
     }
@@ -135,8 +135,12 @@ sub simulate {
     my %Oplist = (
         oct("004") => \&dac,
         oct("010") => \&jms,
+        oct("010") => \&dzm,
         oct("020") => \&lac,
+        oct("024") => \&xor,
         oct("034") => \&tad,
+        oct("044") => \&isz,
+        oct("050") => \&and,
         oct("054") => \&sad,
         oct("060") => \&jmp,
         oct("070") => \&iot,
@@ -178,7 +182,7 @@ sub dump_memory {
 # Load AC
 sub lac {
     my ( $instruction, $addr, $indaddr ) = @_;
-    dprintf( "PC %06o: lac %05o (value %06o) into AC\n",
+    dprintf( "PC %06o: lac %06o (value %06o) into AC\n",
         $PC, $indaddr, $Mem[$indaddr] );
     $AC = $Mem[$indaddr];
     $PC++;
@@ -187,7 +191,7 @@ sub lac {
 # Deposit AC
 sub dac {
     my ( $instruction, $addr, $indaddr ) = @_;
-    dprintf( "PC %06o: dac AC (value %06o) into %05o\n",
+    dprintf( "PC %06o: dac AC (value %06o) into %06o\n",
         $PC, $AC, $indaddr );
     $Mem[$indaddr] = $AC;
     $PC++;
@@ -196,12 +200,30 @@ sub dac {
 # Add to AC
 sub tad {
     my ( $instruction, $addr, $indaddr ) = @_;
-    dprintf( "PC %06o: tad AC (value %06o) from addr %05o\n",
-        $PC, $AC, $indaddr );
+    dprintf( "PC %06o: tad AC (value %06o) with addr %06o (%06o)\n",
+        $PC, $AC, $indaddr, $Mem[$indaddr] );
     $AC= ($AC + $Mem[$indaddr]) & MAXINT;
     $PC++;
 }
 
+# And AC and Y
+sub and {
+    my ( $instruction, $addr, $indaddr ) = @_;
+    dprintf( "PC %06o: and AC (value %06o) with addr %06o (%06o)\n",
+        $PC, $AC, $indaddr, $Mem[$indaddr] );
+    $AC &= $Mem[$indaddr];
+    $PC++;
+}
+
+# Xor AC and Y
+sub xor {
+    my ( $instruction, $addr, $indaddr ) = @_;
+    dprintf( "PC %06o: xor AC (value %06o) with addr %06o (%06o)\n",
+        $PC, $AC, $indaddr, $Mem[$indaddr] );
+    $AC ^= $Mem[$indaddr];
+    $PC++;
+}
+
 # Skip if AC different to Y
 sub sad {
     my ( $instruction, $addr, $indaddr ) = @_;
@@ -209,6 +231,21 @@ sub sad {
     $PC += ($AC != $Mem[$indaddr]) ? 2 : 1;
 }
 
+# Deposit zero in memory
+sub dzm {
+    my ( $instruction, $addr, $indaddr ) = @_;
+    dprintf( "PC %06o: dzm into %06o\n", $PC, $indaddr);
+    $Mem[$indaddr]= 0;
+}
+
+# Index and skip if zero
+sub isz {
+    my ( $instruction, $addr, $indaddr ) = @_;
+    dprintf( "PC %06o: isz %06o\n", $PC, $Mem[$indaddr]);
+    $Mem[$indaddr]++; $Mem[$indaddr] &= MAXINT;
+    $PC += ($Mem[$indaddr] == 0) ? 2 : 1;
+}
+
 # Jump
 sub jmp {
     my ( $instruction, $addr, $indaddr ) = @_;
@@ -253,6 +290,21 @@ sub special {
         $PC += ( $AC == 0 ) ? 2 : 1;
         return;
     }
+    if ( $instruction == 0741400 ) {    # szl: Skip when $LINK is zero
+        dprintf( "PC %06o: szl LINK %0o\n", $PC, $LINK );
+        $PC += ( $LINK == 0 ) ? 2 : 1;
+        return;
+    }
+    if ( $instruction == 0740400 ) {    # snl: Skip when $LINK not zero
+        dprintf( "PC %06o: snl LINK %0o\n", $PC, $LINK );
+        $PC += ( $LINK != 0 ) ? 2 : 1;
+        return;
+    }
+    if ( $instruction == 0741000 ) {    # ska: skip always
+        dprintf( "PC %06o: skp\n", $PC );
+        $PC += 2;
+        return;
+    }
     if ( ($instruction >= 0760000) && ($instruction <= MAXINT) ) {    # law: load word into AC
         dprintf( "PC %06o: law %06o into AC\n", $PC, $instruction);
         $AC = $instruction;