mount output on my usb stick:
rootfs on / type rootfs (rw)
tmpfs on / type tmpfs (rw,size=689208k)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,mode=600)
tmpfs on /dev/shm type tmpfs (rw)
/dev/sdb1 on /mnt/sdb1 type vfat (rw,fmask=0000,dmask=0000,allow_utime=0022,codepage=cp437,iocharset=iso8859-1)
/dev/loop0 on /tmp/tcloop/cairo type squashfs (ro)
/dev/loop1 on /tmp/tcloop/expat2 type squashfs (ro)
/dev/loop2 on /tmp/tcloop/fontconfig type squashfs (ro)
/dev/loop3 on /tmp/tcloop/glib2 type squashfs (ro)
/dev/loop4 on /tmp/tcloop/graphics-libs-1 type squashfs (ro)
/dev/loop5 on /tmp/tcloop/libglade type squashfs (ro)
/dev/loop6 on /tmp/tcloop/libxml2 type squashfs (ro)
/dev/loop7 on /tmp/tcloop/pango type squashfs (ro)
/dev/loop8 on /tmp/tcloop/pixman type squashfs (ro)
/dev/loop9 on /tmp/tcloop/tint2 type squashfs (ro)
/dev/loop10 on /tmp/tcloop/915resolution type squashfs (ro)
/dev/loop11 on /tmp/tcloop/atk type squashfs (ro)
/dev/loop12 on /tmp/tcloop/gtk2 type squashfs (ro)
/dev/loop13 on /tmp/tcloop/libstartup-notification type squashfs (ro)
/dev/loop14 on /tmp/tcloop/ttf-bitstream-vera type squashfs (ro)
/dev/loop15 on /tmp/tcloop/Xlibs_support type squashfs (ro)
/dev/loop16 on /tmp/tcloop/libxcb type squashfs (ro)
/dev/loop17 on /tmp/tcloop/libxcb-util type squashfs (ro)
/dev/loop18 on /tmp/tcloop/openbox type squashfs (ro)
/dev/loop19 on /tmp/tcloop/file type squashfs (ro)
/dev/loop20 on /tmp/tcloop/shared-mime-info type squashfs (ro)
/dev/loop21 on /tmp/tcloop/rox-filer type squashfs (ro)
I can't check my hard disk frugal install ATM but I konw it exhibits rw on /dev/shm as well.