Below is the output of snmpbulkwalk using jnxOperatingDRAMSize and jnxOperatingMemory
jnxOperatingMemory shows correct results whereas jnxOperatingDRAMSize shows in negative. as per juniper documentation jnxOperatingDRAMSize is deprecated
(https://www.juniper.net/documentation/en_US/junos/information-products/topic-collections/release-notes/15.1/junos-release-notes-14.2.pdf)
/usr/bin/snmpbulkwalk -v2c -c MYPUBLICSTRING -OUsb -m JUNIPER-MIB -M /opt/librenms/mibs/junos -t 30 MYJUNIPERIP jnxOperatingDRAMSize
##############################
#result with 0 value removed#
##############################
jnxOperatingDRAMSize.7.2.0.0 = INTEGER: -1409286144
jnxOperatingDRAMSize.7.4.0.0 = INTEGER: -1409286144
jnxOperatingDRAMSize.9.1.0.0 = INTEGER: -244318208
jnxOperatingDRAMSize.9.2.0.0 = INTEGER: -244318208
/usr/bin/snmpbulkwalk -v2c -c MYPUBLICSTRING -OUsb -m JUNIPER-MIB -M /opt/librenms/mibs/junos -t 30 MYJUNIPERIP jnxOperatingMemory
##############################
#result with 0 value removed#
##############################
jnxOperatingMemory.7.1.0.0 = INTEGER: 172032
jnxOperatingMemory.7.2.0.0 = INTEGER: 2752
jnxOperatingMemory.7.3.0.0 = INTEGER: 172032
jnxOperatingMemory.7.4.0.0 = INTEGER: 2752
jnxOperatingMemory.9.1.0.0 = INTEGER: 3863
jnxOperatingMemory.9.2.0.0 = INTEGER: 3863